Traffic Use of Rest Areas on Rural Highways

Rest areas provide the occupants of passenger vehicles and the operators of heavy vehicles an opportunity to use a restroom, walk around, stop for a meal, sleep for a while, or pause to use a cellular phone. These activities have a direct impact on several aspects of the design of rest areas, from parking to facility sizing, water needs, and wastewater generation and handling. All these components are directly influenced by one critical factor: entering traffic volumes. The study presented here used data from 44 study sites to examine the amount of traffic that used rest areas, expressed as the percentage of the main-line hourly volume that entered the rest area, as well as the effect of many underlying variables that were believed to affect the use of rest areas. The study found that the average rate of rest area use by main-line traffic for different highway categories (high- and low-volume Interstates and arterials) varied from 8.4% to 12.3%. For main-line traffic entering rest areas, the overall average rate of use was approximately 10% and the overall 85th percentile was about 15%. The study identified two peaks during the day for the percentage of main-line traffic using the rest area, but vehicular counts at rest areas showed only one peak at about midday. Given this peak demand, the midday period should be considered in the planning and design of rest area facilities. For the majority of rest areas examined, the average rate of use during the midday period varied roughly from 13% to 17% of main-line traffic.