University of California Transportation Center

Transportation engineers and urban planners often report uncertain estimates as precise numbers, and unwarranted trust in the accuracy of those precise numbers can lead to bad transportation and land-use policies. This paper presents data on parking generation and trip generation rates to illustrate the misuse of precise numbers to report statistically insignificant estimates . Beyond the problem of statistical insignificance, parking and trip generation rates typically report the parking demand and vehicle trips observed at suburban sites with ample free parking and no public transit. These parking and trip generation rates are therefore useful guides for planning a city where everyone will drive everywhere they go and park free when they get there.