4.0 ANALYSIS OF COMMERCIAL TRUCK PARKING SUPPLY AND DEMAND

4.1 INTRODUCTION

The methodology used to analyze where shortages exist or are expected to exist involved a four-step process. First, estimates of parking demand over roadway segments were developed using the demand modeling approach described earlier. Second, estimates of parking supply were gathered for each segment using the data sources discussed previously. Third, a summary of the supply and demand for each roadway segment was provided to partners for review, verification, and comment. The partners provided important feedback to account for the knowledge and experience of the local traffic parameters used to estimate parking supply and demand, and this feedback was used to further refine the demand model. Fourth, final calibration of the demand model was completed, and the results of analyses based on this final calibration were used in this report.

Note that the results of these analyses were meant to assist in developing strategies and plans to reduce or better manage any shortages. The information provided was not intended to provide a sufficient level of detail to define the specific location and quantity of truck parking spaces required at any particular location. Design level detail required to complete this type of needs assessment was not practical within the time frame and resources of this study. However, the supply and demand information provided at the corridor level did fulfill the goal of identifying system-level problems and needs that can serve as the basis for the formulation of policy alternatives and the conduct of more detailed study at a later time. In fact, many of the partners used the supply and demand results described above for exactly this purpose.

4.2 DETERMINING CURRENT LEVEL OF OVERCROWDING

The analysis for overcrowding compared the demand and supply results described in the previous sections by examining the ratio of estimated parking space demand (from the demand model) and parking space supply (from the supply survey). This ratio was labeled the Demand/Supply Ratio. A value significantly less than 1 indicates that the demand for spaces is less than the supply (i.e., there is a surplus of spaces). A value significantly greater than 1 indicates that the demand for spaces is greater than the supply (i.e., there is a shortage of spaces), and a value near to 1 indicates that demand nearly equals supply (i.e., there are sufficient, but not a surplus of, spaces). Table 7 lists the values used to classify parking space utilization in this analysis.

Table 7. Threshold values used to classify parking space utilization

4.3 NATIONAL SUMMARY OF OVERCROWDING

The Demand/Supply Ratio and the classification method described above were used to evaluate the overall degree of truck parking space utilization for each State by comparing the total demand and total supply for the State. The results of the State-by-State analysis are listed in Table 8.

Table 8. Evaluation of parking shortages: State-by-State analysis

¹ The supply of parking spaces at commercial truck stops and travel plazas was not determined for Alaska.

Table 9. Evaluation of current parking shortages: National summary

¹ Alaska did not report on the number of parking spaces available at commercial truck stops and travel plazas

Nationally, the greatest shortages appear to be in the Northeast and the Midwest. Shortages also appear to be greater on non-Interstate highways, where the estimated National demand of 9,643 for public spaces far outstrips the estimated supply of 2,853 spaces, the estimated demand of 32,284 for private spaces also outstrips the estimated supply of 24,002 spaces.^d

The demand model was also used to estimate demand for commercial vehicle parking 20 years into the future based on State estimates for the increase in truck volume during that period, and the resulting estimates were used to calculated an estimated annual growth rate in the demand for truck parking. These estimates project an average growth rate of 2.7 percent, with rates for individual States varying from 0.5 to 4.4 percent. For comparison, the annual growth in supply of parking spaces at public rest areas is estimated at 1 percent, and the growth at commercial truck stops and travel plazas is estimated at 6.5 percent.

4.4 RESULTS FROM THE DRIVER SURVEY

Several hundred drivers provided written and verbal comments, both solicited and unsolicited, regarding the availability of truck parking. Overwhelmingly, drivers remarked that there are not enough parking spaces at public rest areas or commercial truck stops and travel plazas. Drivers complained of a lack of parking availability particularly in the overnight hours. Drivers also reported that more parking is needed near metropolitan areas and in certain regions of the country (e.g., Northeast, Southern California, Northwest).

Drivers were asked how frequently they encounter available parking at public and private truck parking facilities (Table 10). Among the overall sample, only 11 percent of respondents indicated that they frequently or almost always find available parking at public rest areas and only about one-third of respondents reported that they frequently or almost always find available parking at commercial truck stops. Nearly 90 percent of respondents indicated that they only sometimes, rarely, or almost never find available parking at public rest areas. While two-thirds reported that they only sometimes, rarely, or almost never find available parking at commercial truck stops.

Table 10. Frequency with which drivers find available parking at public rest areas and commercial truck stops

Drivers also had the opportunity to rate how often their next stop (e.g., shipper or receiver) has available parking. The most frequently reported response (by 40 percent of sample) was that sometimes their next stop has available parking. Thirty-seven percent of drivers reported that their next stop has available parking rarely or almost never. Twenty-three percent indicated that their next stop has available parking frequently or almost always.

4.5 SUMMARY AND CONCLUSIONS

This section has presented the results of a National comparison of parking supply and demand, which indicates that a shortage of parking at public rest areas may exist in up to 35 States and a shortage of total parking may exist in up to 12 States. Shortages of parking at commercial truck stops and travel plazas are less common and, to the extent they are interchangeable, may offset shortages in parking at public rest areas.

This imbalance in parking availability is underscored by the results of the driver survey. Drivers were asked how frequently they encounter problems in obtaining parking spaces at public and commercial truck parking facilities. Nearly 50 percent of the respondents indicated that parking is rarely or almost never available at public rest areas. Approximately 15 percent reported parking is rarely or almost never available at commercial truck stops and travel plazas.

It is estimated that the demand for truck parking spaces will continue to grow at an average rate of 2.7 percent nationally, creating new demand for parking at both public rest areas and commercial truck stops and travel plazas. While estimates of the growth rate of parking spaces at commercial truck stops and travel plazas will accommodate the increased demand for private parking, the increased demand for public parking will exacerbate the supply shortages already apparent for public parking unless either (a) additional public spaces are made available or (b) steps are taken to encourage drivers to better utilize the existing supply of private spaces. The following section contains recommendations developed by various State partners to address these current and future shortages.

[d] In the case of non-Interstate highways, greater access to other sources of public and private parking spaces may help offset some of the apparent shortage.