Compared to car travel, the findings indicate high variability and uncertainty associated with paratransit trip times. For the same origin-destination pairs, mean paratransit trip time is almost twice that of mean car travel time with a standard deviation for paratransit trip time fourfold that of the standard deviation for car trip time. For perspective, traveling an average 10 miles during the 7-8 AM morning peak can take about 16 minutes by car with almost no variability, while that same trip can take on an average 25 minutes by paratransit, with 5% trips being outside the 95% confidence interval, and thus unpredictable.
Paratransit trip time inefficiency tends to be particularly worse for females; older adults; those making trips between 9-11 AM; cash-paying customers; those making shorter trips; and for those travelling during inclement weather, including cold temperatures. The findings suggest a need to re-assess using public transit as a benchmark for paratransit supply as regulated by the ADA.