Study of the Effectiveness of Nighttime and Truck Speed Limits

摘要

The repealing of the national minimum speed limits in the U.S. gave states the freedom to set their own speed limits on non-interstate highways. Texas adopted different speed limits for cars and trucks dependent on the time of day. The purpose of this study is to evaluate, if the drivers are following the different speed limits during day and night time on various types of highways. Speed data were collected on the following highways: Interstate Highway-137, Multilane Divided Highway-US 77, Farm Road-FR 665 and FR 70. Various statistical methods were applied to analyze the collected speed data. It was found that the most of car drivers on highways and truck drivers on farm roads do not follow the posted speed limits. The 85th percentile of traveling speed on the studied highways and farm road is 70mph ±2mph with irrespective of type of vehicle and time of the day.