Accidents at Entrance Ramps in Long-Term Construction Work Zones

Presented in this paper is an analysis of accidents in entrance ramp areas on two long-term freeway reconstruction projects in Texas. Entrance ramp areas were compared with nonentrance ramp areas to determine the proportionality of accident increases during construction. Accident data were collected for each project for 2 or 3 years before construction and for the duration of the construction phases studied. The two projects studied were on I-35W in Ft. Worth, Texas, and I-45 in Houston, Texas. Accident frequencies increased 35% in nonentrance ramp areas and 61% in areas of entrance ramps remaining open on I-35W during construction. Both increases were statistically significant at “a” equals 0.05. On I-35W, accident frequency increases were disproportionately higher in entrance ramp areas during construction (30% higher than increases in nonentrance ramp area accidents, statistically significant at “a” equals 0.05). Additionally, on I-35W, property damage only accidents, severe accidents, daytime accidents, and multivehicle accidents (other than rear-end accidents) increased is proportionately in entrance ramp areas during construction. Conversely, accident frequencies did not increase significantly (“a” equals 0.05) in either nonentrance ramp areas or entrance ramp areas considered as a group on I-45. No category of accident was found to have disproportionately increased in nonentrance ramp areas or entrance ramp areas on I-45.