Effectiveness of a speed monitoring display in roadwork zones on single carriageway rural roads in a short urban segment

Excessive speed and human error are the primary causes of crashes on roadwork zones. The speed monitoring display (SMD) is a usual traffic calming measure to enhance speed limit compliance. Its effectiveness has been verified in urban areas and in short urban segments, and it is suggested as a measure with low to medium effects on roadwork zones. This paper aims to analyse the SMD's effect in a short urban segment of a single carriageway highway with roadwork. The assessment involved comparing the speed values throughout the roadwork zone with only the compulsory signage (Phase 0), when incorporating a SMD (Phase 1), and four months after (Phase 2). The results confirmed its efficacy, with a 5% decrease where the SMD was installed. The SMD's effect persisted in the following weeks after its introduction (Phase 1), and in the entire roadwork zone four months after (Phase 2). The lowest speed values on the segment were recorded at the works' centre, and they decreased during working hours (8:00 a.m. to 6:00 p.m.), contributing to road workers' safety. Conversely, speed values were not impacted in the opposing direction. Consequently, SMD implementation is recommended for both directions in single carriageway roadwork zones.