Date of Award


Degree Name

Master of City and Regional Planning/MS in Engineering (Transportation Planning Specialization)


City and Regional Planning


Cornelius Nuworsoo


In California, there is an observed trend in which collisions cluster in and around tunnels. The break in road continuity created by the tunnels disturbs traffic flow that can lead to collisions. One of the main contrasts between open roads and tunnel roads occurs in lighting. Drivers with sight deficiencies are unable to adapt their sight to the change in the lighting environment and may crash due to misperception of road alignment, vehicle’s speed and other physiological reactions, such as tension. The suspect population group of crashes occurring under the influence of tunnels conditions is older drivers.

The literature suggests that sight and driving performance deteriorate with age. This research attempted to validate this claim by performing a study that looked at driver and crash characteristic of injury and fatal collisions that occurred in and around tunnels. The expectation was that a greater proportion of the older population, 60 years and older, would be represented in the crash data. However, this study found that it is young drivers and not older drivers who are more likely to crash in and around tunnels. This finding may be explained by the State of California’s vision requirements for the issue of a driver’s license, and the voluntary retirement of drivers that feel that they can no longer drive safely. A second explanation may be that high-risk taking behavior exhibited in younger drivers overcompensates for the physical impairments exhibited in older drivers.