This paper analyses pedestrian exposure to carbon monoxide (CO) from vehicle emissions in a single intersection scenario. There is clearly a trade off between pedestrian exposure and the reduction in emissions as a resultof smooth traffic flow; achieved usually by employing longer signal cyclelengths. Long signal cycles, resulting in less total vehicle emissions, cause increased pedestrian delay and longer exposure to (slightly reduced) emissions. Measuring this trade off would require devising values of time for pedestrians in terms of exposure to harmful emissions such as CO in addition to delays in terms of lost time. The work has also highlighted a number of intersection traffic control measures that allow smooth traffic flows and reduce vehicle delays but increase pedestrian exposure to vehicleemissions. The first is the use of long signal cycle times which has already been discussed. The second is the use of parallel pedestrian phase where pedestrians cross the road only when the vehicular traffic on the parallel road is also moving. This technique further allows for dividing a single road crossing into two multiple arms and pedestrians have to wait twiceto cross a single road; once at the curb and again at the refuge while also increasing their geometric delay through staggering of the median refuge and hence further increasing their exposure. The ultimate objective of this work is to propose a pedestrian friendly traffic control system that adapts to reduce pedestrian exposure while balancing the need for a reduction in vehicle emissions. For the covering abstract see ITRD E134653.
Samenvatting