An Assessment of the Need for a Sunscreen at the Hampton Roads Bridge-Tunnel

About the report:

Several aspects of the Hampton Roads Bridge-Tunnel facility were investigated to determine if a sunscreen was needed at the north entrance to the second tube. The analysis included accident records, measurements of the speed of vehicles entering the north portal of the old tube, photometric characteristics of this entrance, a study of visual performance while entering the tunnel, and the results of a survey of motorists using the facility. The survey and visibility studies indicated that severe difficulty in seeing into the tunnel is experienced under some conditions. Accident records showed that this difficulty has not been a significant safety hazard, but radar measurements revealed a significant reduction in speed at the approach to the mouth of the tunnel. This slowdown was attributed to difficulty in seeing into the tunnel, and to a perceived constriction of the roadway caused by the narrow curved descent to the portal and the presence of oncoming traffic. The perceived constriction of this roadway will be reduced when the second tube is opened. The investigators recommend lighter surfaces of the tunnel walls at the portal and edge striping of the roadway as ways of increasing visibility into the tunnel. In spite of the existence of a real visibility problem, they do not recommend construction of a sunscreen until these simple modifications have been evaluated.

Authors