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3.0 State Practices to Reduce Wet Weather Skidding Crashes - State Practices to Reduce Wet Weather Skidding Crashes

<< Section 2.0 – Components of a Wet Weather Crash Reduction Program Table of Contents Section 4.0 – Summary >>

3.0 State Practices to Reduce Wet Weather Skidding Crashes

This section describes the current state practices for reducing wet weather skidding crashes used in California, Florida, Michigan, New York, and Virginia and provides some additional state practices used to identify and mitigate wet crash locations.

3.1 California

In 1972, Caltrans developed their Traffic Accident Surveillance and Analysis System (TASAS) to identify high-collision concentration locations. Included in this system was a methodology for identifying locations with a high concentration of wet crashes known as Wet Table C.

Identification of Wet Weather Crash Locations

Caltrans State Office of Traffic Safety Program analyzes the crash data to develop the Wet Table C on an annual basis. The Wet Table C identifies locations with a minimum of 9, 6, or 3 wet crashes within a 36-, 24-, or 12-month period, respectively and are significantly higher than the statewide average. Wet collisions are identified by those with a road surface coded as “wet.”

A significance test is conducted to determine if the defined highway segments, ramps, or intersections have a wet crash count significantly higher than the number of crashes required for significance (NR). For a segment to have significantly high crashes, the segment crash count must be greater than or equal to NR. NR was derived from the Poisson’s distribution one-tail test for a 99.5 percent confidence interval and is defined by the following equation:

Equation - The number of crashes required for significance is equal to the average number of crashes plus 2.57 times the square root of the average number of crashes plus 1.329.

Where,

NR = Number of crashes required for significance; and

NE = Average number of crashes.

NE is calculated using the following equation:

Equation - The average number of crashes is equal to the average daily traffic in vehicle per day times the analysis period in days times the segment length in miles times the average wet crash rate times 10 to the negative sixth power.

Where,

ADT = Average daily traffic (vehicles per day);

t = Analysis period (days);

L = Length (miles); and

RE(wet) = Average wet crash rate (wet crashes/million vehicles or wet crashes/million vehicle miles).

RE(Wet) is calculated as follows:

Equation - The average wet crash rate is equal to the 0.3 times the difference between 1.0 and the decimal percentage of wet time plus 3.2 times the base crash rate for the specific highway segment type all divided by the sum of one plus 2.2 times the decimal percentage of wet time.

Where,

wt% = Percentage of wet time (decimal).

RE is calculated as:

Equation - The base crash rate for the specific highway segment type is equal to the adjustment factor for the specific highway segment type divided by the average daily traffic for the specific segment.

Where

Base rate = Base crash rate for specific highway segment type (provided by TASAS);

ADT factor = Adjustment factor for specific highway segment type (provided by Caltrans tables); and

Total ADT = Average daily traffic for the specific segment (provided by TASAS).

The percent of wet time is determined for each county in the State. The percent of wet time was initially developed in 1972 using 11 years of data from 1957 to 1967. In 2008, Caltrans conducted a study with the assistance of the Western Transportation Institute at Montana State University to update the percent of wet time values to reflect current climatic trends. The 2008 values were not found to be significantly different than the 1972 values [5].

The analysis is based on crash data from July 1 to June 30, so that the entire wet season is included in each analysis period. The analysis starts at the beginning of a route and evaluates one 0.2‑mile segment at a time using a sliding scale of 0.02 miles. If the first 0.2‑mile segment is not found to be significant, the analysis moves ahead 0.02 miles and evaluates the next 0.2‑mile segment. If a segment is found to be significant it is added to the output table. This process is repeated for the entire roadway length.

The results of the analysis are documented in an annual report. The report is sent out to the 12 districts in August or September; this time period corresponds with the wet season and is appropriate for conducting field reviews. The districts conduct data analysis of the locations and perform field reviews to identify recommended safety improvements.

Friction Testing Procedures

As part of their highway inventory, Caltrans maintains an active friction data set for the outer two lanes of the highway network with one test per lane-mile. The program tries to maintain a regular rotating schedule of every three years; however, staffing and equipment issues have had a profound impact on the schedule. Skid testing is also conducted at locations identified with wet high-collision concentration locations; however, an active file of these testing locations is not kept. For their highway inventory and wet weather crash investigations, Caltrans uses a locked wheel towed trailer tester with ASTM standard ribbed tires according to ASTM E 274 procedures.

Investigation and Remedial Action of Wet Weather Crash Locations

The list of locations identified in the Wet Table C is provided to the District Traffic Safety Engineers to follow up with a safety investigation. Locations identified in the Wet Table C are evaluated within a 12-month period. For each location, the investigator gathers and analyzes relevant data in an effort to identify contributing factors and potential countermeasures. The Caltrans Traffic Safety Program [6] provides recommended procedures for conducting site investigations. Several processes are used to identify the most effective improvement strategy. This includes a detailed analysis of the collision history, collision diagrams, friction test results, field investigations, and a review of roadway geometrics at the site to assist in identifying collision patterns that may susceptible to correction. Additional data elements such as time of day, direction of travel, movement preceding collision, or other factors may help in investigating crash patterns.

To mitigate the locations identified in the Wet Table C where improvements are recommended, Caltrans typically implements pavement improvements such as superelevation changes, open-grade asphaltic concrete (OGAC) overlays, pavement grooving, high-friction surface treatments, or drainage improvements. Caltrans also installs “Slippery When Wet” signs if recommended by an investigation and will consider a reduction in the posted speed limit, if justified by a spot speed study.

Project and Program Evaluations

Caltrans evaluates wet weather crash location improvements that are funded through the HSIP program. These evaluations compare three years of both before and after improvement crash data using total, fatal, injury, and property damage only (PDO) crashes. However, Caltrans does not evaluate individual projects or subprograms; the safety program is evaluated as a whole.

3.2 Florida

The State Safety Office conducts an analysis to identify wet weather crash locations on the state roadway network using Florida’s Crash Analysis Reporting (CAR) System. The State Safety Office provides a report to the District Safety Engineers (DSEs) on an annual basis. However, the CAR system also provides the DSEs with the ability to conduct analyses of wet weather crashes in their districts at their discretion.

Identification of Wet Weather Crash Locations

The State Safety Office conducts an analysis of wet weather crashes on the state roadway network using five years of crash data through the CAR system. The analysis identifies sections with either a minimum of four wet weather crashes with 25 percent or more wet weather crashes or 50 percent or more wet weather crashes during a five-year period. The analysis uses a sliding window with 0.3‑mile segments and increments of 0.1 miles. Intersections are included in the segment analysis. The State Safety Office conducts the analysis on an annual basis and provides a report to the DSEs. The CAR system also allows the DSEs to run an analysis to identify wet weather crash locations in their districts at any given time. For example, to identify wet weather crash locations, District 5 (Orlando/Daytona Beach area) runs an analysis on a quarterly basis, and District 7 (Tampa area) runs an analysis on a monthly basis. The DSEs then make requests to the State Materials Office to conduct friction tests at the locations identified through the crash analysis.

Friction Testing Procedures

The Florida DOT State Materials Office maintains a database of skid test results and conducts skid tests on all state roadways on a three-year rotating schedule. The friction testing procedures are outlined in the Skid Hazard Reporting System User Documentation [7]. Skid tests are typically conducted at a speed of 40 miles per hour in the left wheel path using a standard two-wheel trailer towed by a one-ton pick-up truck conforming to ASTM E 274 requirements. Testing equipment is calibrated in-house at intervals of 30 to 45 days per ASTM specifications. The normal testing procedure is to conduct three tests per mile or section (if less than a mile). A mean friction value is determined based on the arithmetic average of the tests conducted on a section of roadway. In addition to the routine test schedule, tests are also conducted when:

The DSEs review the most recent friction test results of the identified segments to determine if the friction number is low, 28 (FN40R) or less for posted speed limit of 45 miles per hour or less and 30 (FN40R) or less for posted speed greater than 45 miles per hour.

Investigation and Remedial Action of Wet Weather Crash Locations

If the friction number is low for locations identified through the crash analysis, the DSEs review the work program to determine if the roadway is programmed for resurfacing. When the location is not included in the work program, the DSE must further investigate the site to identify potential contributing crash factors. The DSE reviews the traffic crash reports and field conditions (e.g., geometrics, surface condition, drainage, etc.). If inadequate pavement friction is identified as a contributing factor, the DSEs identify the appropriate mitigation techniques.

Florida has developed high-friction surface treatments for ramps, curves, or other locations with wet weather crashes. A specification for asphalt concrete friction courses has been developed to support this effort. Specific provisions are provided for using different aggregates, including granite. However, the specification does not specifically address the required friction value at the conclusion of compaction and rolling. Some of the districts use granite in the friction course if a skid hazard exists. The percent of granite changes in different parts of the State. Higher percentages of limestone aggregate are used in the southern part of the State, where the source mines are locally available. Florida is currently working on specifications for hybrid mixes with granite and limestone. As a temporary improvement, the District Maintenance Engineer will install warning signs at locations with a low friction number until a project can be implemented to improve the pavement surface friction.

The District 4 office (Broward County) has experimented with the use of high-friction surface treatments (HFST) in areas where friction-based crashes are a concern [8]. The HFST used a modified exothermic epoxy resin as a binder material and was top dressed with specific aggregates. Evaluation data found significant friction number increases after the application of the HFST. For example, one location reported a friction number of 35 (FN40R) before the treatment and a friction number of 104 after application. Evaluations concluded the HFST was effective in increasing the friction value of the roadway.

Typically it takes about two and one-half to three years to implement a resurfacing project (one year for programming, one year for design, and one year for construction). Currently, District 7 is piloting a design build or “push button” program. With this program, multiple projects are programmed at one time; allowing design and construction to occur within nine months.

Project and Program Evaluations

Florida DOT developed a web-based database application called the Crash Reduction Analysis System Hub (CRASH), which is used to record and maintain safety improvement projects, update crash reduction factors (CRF), and apply CRFs to conduct a benefit/cost analysis of proposed safety improvement projects. The DSEs input all HSIP-funded projects, including improvements for wet weather crash locations, into CRASH. CRASH uses before and after crash counts to evaluate the safety projects and develop CRFs for the countermeasures implemented. The CRFs are typically calculated based on five years of both before and after data, but the system administrator may specify any specific time period for the calculation.

Florida has not conducted any recent formal evaluations of their Skid Hazard Elimination Program but anticipates conducting an evaluation over the next year. Although not a formal process, typically the status of previously identified wet pavement crash locations are investigated to determine how many remain from year to year.

3.3 Michigan

Michigan DOT has a long-standing program for addressing wet weather crashes that has been in place for approximately 25 years. The Safety Programs Section leads the program and develops a list of locations for the regions to investigate.

Identification of Wet Weather Crash Locations

The identification of potential wet weather crash locations is carried out by Michigan DOT’s Safety Programs Section. The identification of locations is based on the results of the statewide friction testing program. Annually, the Safety Programs Section develops a list of locations with a skid number of less than 30 (SN40R). This list is then provided to each of the regions to investigate further and evaluate the need for action.

Friction Testing Procedures

Michigan DOT conducts friction testing on each lane of all state-maintained roadways on a three-year cycle (approximately one-third of roads each cycle). The tests are conducted using a Dynatest 1295 (locked wheel) friction tester according to ASTM E 274 requirements. Tests are conducted using an ASTM E 501 ribbed tire for level testing and an ASTM E 524 smooth tire for special testing. Friction tests are also conducted on corridors, spot locations, or intersections identified with a potential rear-end wet weather crash problem. The skid test results are available on the Michigan DOT network for regions to review.

Typically friction tests are not conducted on new construction or resurfacing projects, unless by special request. To ensure adequate surface friction, Michigan developed and implemented a wear track-based polishing test called the Michigan Aggregate Wear Index (AWI). The AWI is used to evaluate aggregates used in the top surface of hot mixed asphalt pavements. Each source of aggregate is tested and assigned AWI values which are updated as quarrying progresses into new areas. There is also a process to assign an AWI value to blended aggregates.

Investigation and Remedial Action of Wet Weather Crash Locations

The investigation of the sites identified by the Safety Programs Section with a skid number of less than 30 (SN40R) is carried out by the individual regions. The regions consider four factors in the evaluation:

  1. Wet surface friction tests result is less than 30 (SN40R);
  2. Estimated reduction in wet crashes is equal to at least three crashes per year per spot (intersection approach) or 0.5‑mile segment location;
  3. A field review to identify factors not related to surface friction qualities, such as “wheel tracking” or a clogged drainage structure that may contribute to a higher percentage of wet crashes; and
  4. The time-of-return on the investment is five years or less.

Michigan DOT developed a tool in Microsoft Excel for determining if the location warrants action. The spreadsheet contains the Region’s wet crashes, wet crash percentages, and total crashes. The analyst must enter data for each of the locations identified based on the friction number, including project location, limits, number of nonwet crashes, number of wet crashes, and analysis period. The spreadsheet then calculates the expected reduction factor used in the time-of-return (benefit/cost) analysis.

If the location warrants action, the regions review the five-year plan to see if a project is scheduled for resurfacing. If the location is included in the schedule, they might be able to schedule the resurfacing at a sooner date. If it is not in the plan, typically the regions will do an overlay, ultra thin overlay, mill and resurface, microsurfacing, paver placed surface seal, chip seal, or diamond grinding. The regions can submit these improvements as part of the annual call for safety projects. Once the regions have decided on a course of action, they must report it and the results of the analysis to the Safety Programs Section.

Michigan DOT is currently working with the FHWA Office of Pavement Technology on a pilot project on surface treatments. The project is focused on freeways ramps with curves. They are currently pilot testing Tyregrip on curves.

Project and Program Evaluations

Michigan conducts before and after evaluations of all safety projects. Michigan has not conducted a recent evaluation of their wet weather crash reduction program; however, the overall number of wet weather crashes has gone down. In addition, fewer locations are being identified each year.

3.4 New York

New York established their Skid Accident Reduction Program (SKARP) in the mid 1990s to address a problem with the aggregate (dolomite) becoming polished. The program identifies and treats wet road crash locations on state-owned roadways and arterials (data is not available for local roads). Program requirements are outlined in Engineering Instruction 02-007, Skid Accident Reduction Program [9].

Identification of Wet Weather Crash Locations

The Office of Modal Safety and Security is responsible for the identification of wet weather crash locations. During April of each year, the Office of Modal Safety and Security analyzes the crash data to identify locations with an unusually high proportion of wet road crashes and develops a Wet Road Accident Priority Investigation Location (PIL) listing. The two primary considerations for identifying high wet road crash locations are the proportion of wet road crashes compared to total crashes and the occurrence of a specified minimum number of wet road crashes over a two-year period. Locations are identified if there are at least six wet road crashes during a two-year period in rural areas and at least 10 in urban areas with at least 35 percent of the total crashes occurring on wet road conditions. The PIL listing is sent to the Office of Technical Services to schedule friction testing for the locations identified on the list.

Friction Testing Procedures

Generally, the Office of Technical Services conducts friction tests from April to November at all locations included on the PIL list. However, there are a couple exceptions:

The tests are conducted with a skid trailer according to ASTM E 274 requirements using a ribbed tire meeting ASTM E 501 requirements. Tests are conducted at 0.1‑mile intervals. The Materials Bureau maintains a file of all friction testing data.

The Wet Road Accident PILs are categorized into two classes depending on the friction test results:

Following the friction testing, the results are transmitted to the regions for review and consideration in the regions’ capital programming and preventive maintenance paving activities. The regions must investigate all locations with a friction number below 32. All sites with a friction number less than 26 must be remediated immediately. A friction number of 32 provides a stopping distance consistent with AASHTO design standards for highway sight distance and is consistent with design requirements for curves. A friction number of 26 was identified as a threshold coefficient of crash frequency based on analysis of wet weather PIL locations that had been friction tested.

Friction tests are not routinely conducted on resurfacing projects but are done occasionally. To provide for adequate surface friction, New York evaluates every aggregate source for both asphalt and concrete pavements. Petrographic evaluations are conducted on a biennial basis to qualify aggregates for the Approved List of Fine and Coarse Aggregates and on plant samples to provide quality assurance (QA) of aggregates during production for state contracts. Friction performance is monitored annually on selected sections in the Pavement Friction Inventory.

Investigation and Remedial Action of Wet Weather Crash Locations

The Wet Road Accident PIL listing and the results of the friction tests are forwarded to the Regional Offices for consideration in the regions’ capital programming and preventive maintenance paving activities. The region’s investigate the locations on the PIL listing and are responsible for identifying and implementing remedial actions.

The remedial actions of wet road crash locations typically include resurfacing with one and one-half inches of hot mix asphalt using the appropriate friction aggregates, or a thin cold emulsion microsurfacing (using noncarbonate aggregates). Superpave hot mix asphalt is the standard for New York State contracts.

The regions are required to report on pending and completed remedial actions for all locations including in the PIL listing to the Office of Modal Safety and Security in May each year.

Project and Program Evaluations

New York conducts evaluations of SKARP projects funded through the HSIP. The evaluations are based on three years of before improvement fatal and injury crash data and three years of after improvement fatal and injury crash data. As part of the analysis, a benefit/cost ratio is calculated to determine if the project achieved its purpose. If the projects are not part of the HSIP, evaluations are conducted at the discretion of the region.

New York conducted a formal evaluation of the program in 2002 but has not since evaluated the overall program. The previous evaluation developed crash modification factors for resurfacing with high wet road crash locations based on the evaluation of 40 improved sites. The results indicated that resurfacing treatments at wet road crash locations are expected to reduce total crashes by approximately 20 percent, total wet road crashes by approximately 60 percent, and severe (fatal and injury) wet road crashes by approximately 70 percent [10].

Overall, the frictional quality of the State’s pavements has improved since the program’s inception. A summary of PIL testing from 1996 through 2006 shows a steady decline in the number of sites requiring treatment from 91 sites in 1996 to 19 sites in 2006. In 2007, 14 sites required treatment.

3.5 Virginia

In 1976, the Virginia Transportation Research Council (VTRC) developed a procedure for systematically identifying and evaluating wet crash sites or low skid number sites and established the Wet Accident Reduction Program (WARP). The program procedures are outlined in Virginia’s Wet Accident Reduction Program: A User’s Manual [11].

Identification of Wet Weather Crash Locations

The Traffic Engineering Division conducts an analysis of the crash data on an annual basis to identify Potential Wet Accident Hotspots (PWAH). Crashes are located at 0.1-mile intervals and serve as the principal database for identifying PWAHs. The identification process is as follows:

  1. Crashes involving snow and ice are discarded.
  2. Crash files are scanned by district, county, route, and mile point.
  3. When a wet weather crash is registered, an additional 0.2 miles on either side of the site is scanned for additional wet weather crashes.
  4. If one or more wet weather crashes are found, an additional 0.2 miles of the road is scanned for wet weather crashes.
  5. Locations are classified as PWAHs when:
    1. There are a minimum of three wet weather crashes, each separated by less than 0.2 miles; and
    2. The proportion of wet weather crashes (wet/(wet+dry)) is at least 20 percent higher than the ratio for all roads in the area.

Sites meeting these criteria are then friction tested by the Materials Division and locations. Virginia uses the conservative requirement of three wet weather crashes to designate a PWAH so as not to overlook a potentially dangerous condition. While the crash data is the primary source for identifying PWAHs, locations may also be identified based on field requests or Virginia’s ongoing program of annual skid tests of the primary and Interstate systems.

Friction Testing Procedures

The Materials Division conducts skid tests of the PWAH locations. Tests are conducted using an ASTM E 274 trailer unit on a wetted pavement at a speed of 40 miles per hour. Each unit includes force and speed transducers, a control system, a record system, and a pavement wetting system. Test wheels are incorporated into the trailer. The test tire is a standard smooth tire.

Skid units are routinely (weekly, monthly, and yearly) calibrated following the manufacturer’s recommendations. Virginia DOT has a comprehensive calibration and verification program to ensure quality test results.

PWAH locations are tested using the following guidelines:

Locations with a friction number less than 20 (SN40S) are flagged for review by the districts. A friction number of 20 (SN40S) was selected as the threshold, to be consistent with other agencies. However, a more recent study conducted by VTRC and Virginia Tech has recommended use of a higher value (25-30).

The Virginia DOT conducted a study to identify and characterize Virginia’s nonpolishing aggregates in terms of their wet skid resistance for pre-evaluating the skid resistance of nonpolishing aggregates [12]. This was done by comparing the effect of different asphalt mixtures on pavement surface macrotexture using the ASTM E 965‑87 sand patch method and considering the effect of texturing on pavement surface friction. Fifty-seven sources of nonpolishing aggregates, representing 18 lithologies, were studied. Using the ASTM E 274‑90 procedure skid testing of the 18 lithologies was carried out on 1,246 bituminous pavement sections. Aggregate groups with the highest and lowest wet friction rankings were identified.

Investigation and Remedial Action of Wet Weather Crash Locations

After the PWAH are friction tested, the districts are responsible for reviewing the sites with a skid number of 20 (SN40S) or less and making decisions on possible remediation. The State does not mandate resurfacing if the friction is less than 20 (SN40S) without further review. Typically the districts will first check to see if the location is included in the maintenance schedule for resurfacing.

For asphalt pavement, micro surface treatments are widely used to restore pavement with inadequate friction characteristics. Seal coats or chip seals are also used to restore pavement friction characteristics and extend the life of pavements. Pavement preservation activities also provide an opportunity to improve both the pavement condition and surface characteristics in a very cost-effective manner. Depending on the pavement distress condition, the section could also be overlaid.

For Portland Cement Concrete (PCC) pavements, diamond grinding can be used to increase concrete pavement friction by enhancing surface macro texture. Adequate macro texture reduces the potential for hydroplaning. Saw cut grooving is used traditionally to restore adequate frictional characteristics of PCC pavements. Grooving can be either longitudinal or transverse.

If no action can be taken immediately, the district may temporarily put up “Slippery When Wet” signs until a more permanent improvement can be made. Districts have the option to apply for safety improvement program funding to improve these sites. HSIP projects are typically implemented within a three-year timeframe.

Project and Program Evaluations

Project evaluations are conducted for all safety improvements, including WARP projects funded through the HSIP. The evaluations are conducted using three years of both before and after improvement data.

Virginia DOT’s 2007 Wet Accident Reduction Program Report [13] provides a comparison of the 2007 PWAH sites to historical results. The findings include:

3.6 Additional State Practices

While not all of the interviewed states procedures are included in this guide, this section provides some additional notable practices and additional countermeasures being used to address wet weather crashes.

Identification of Wet Weather Crash Locations

New Jersey was the only State to incorporate crash severity into the initial site identification process. New Jersey originally identifies sites with an overrepresentation of wet weather crashes, based on statewide averages, and then ranks the locations by weighting the crash frequency by the crash severity. However, it should be noted that other states may incorporate severity into the process by prioritizing projects using of a benefit/cost analysis.

Kentucky did not have a program specifically focused on wet weather crashes; however, the State recently developed a Roadway Departure Safety Implementation Plan [14], which included the identification of roadway segments for implementing friction treatments to reduce wet pavement crashes. The analysis used to identify roadway sections for friction improvements evaluated 3,000 feet roadway segments and identified sections that met a minimum criterion of eight or more crashes and 35 percent or more occurring on wet pavement during the five-year period between 2004 and 2008. The analysis identified 227 segments for potential friction improvements. Kentucky started to implement the pavement friction improvements during the 2010 construction season, and it is anticipated the plan will be implemented over a five-year period.

Additional Countermeasures to Address Wet Weather Crashes

While the focus of this guide is on surface treatments to reduce wet weather skidding crashes, many of the states identified additional countermeasures to reduce wet weather crashes as a whole.

Florida is currently looking into the development of specifications for wet weather pavement markings to address nighttime, wet weather, and lane departure crashes. Florida also implemented a policy to use audible and vibratory markings on rural roadways (excluding limited access facilities) to address lane departure crashes, but the policy also indicates audible and vibratory pavement marking can be used in areas with a history of wet weather crashes. It is implied that the marking will be more visible and conspicuous during wet weather conditions. Similarly, Florida also uses inverted rib profile markings to improve the conspicuity of lane markings under all weather conditions. As a temporary improvement to address wet weather crashes occurring on the ramps at the interchange of two Interstate routes in FDOT District 5, optical speed bars and variable speed advisory signs were installed until the project can be completed.

In the Detroit metropolitan area, wet weather tape has become the standard pavement marking for freeways to provide for better reflectivity. It is being installed systematically as part of overlay projects.

New York is currently investigating grooved in epoxy pavement markings with wet-night visibility elements mixed with standard glass beads as an option. They have done a few trial placements. The New York State Thruway Authority is now moving to all grooved in epoxy with special retroreflective elements. New York has also been implementing Type 9 sheeting on signs for more visibility and is looking into a policy on rumble strips.

<< Section 2.0 – Components of a Wet Weather Crash Reduction Program Table of Contents Section 4.0 – Summary >>
Page last modified on October 15, 2014
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