Delay Messages and Delay Tolerance at Houston Work Zones (abridgement)

A questionnaire survey of freeway drivers in Houston was conducted at six locations: I-10 W, I-10 E, I-45 N, I-45 S, US-59 S, and US-59 N. The questionnaire data were based on a license-plate survey with 843 driver responses to a mail-in questionnaire. The questions were related to two issues. Specifically, the survey sought to determine ( a) the minutes of delay connoted by the expressions Major Delay and Minor Delay, and (b) drivers delay tolerance, that is, the minutes of delay before a driver would divert from a freeway to a service road. The reason for studying drivers’ responses on three freeways and at six locations was to assess possible regional differences among Houston drivers based on driving experiences unique to the facility. The questionnaire data found no significant differences among the freeway drivers at the six sampled locations. The message Major Delay uniformly meant 22.7 min or more delay time, with a range of 21 to 25 min across locations. The message Minor Delay meant 7.9 min or less delay time, with a range of 7 to 9 min across locations. These time values were largely similar to a previous national survey of the meanings of major and minor as adjectives describing accident severity. Regarding delay tolerance, Houston drivers stated they would divert from the freeway to a service road given news of a delay of 5 or 6 min. Delay tolerance was 10 min less for the Houston sample than for previously researched national samples. Possible reasons for the reduced delay tolerance are discussed.