Quantifying changes in carbon monoxide levels following the installation of SCOOT

This paper describes a study of roadside levels of carbon monoxide to quantify the effect of controlling traffic with demand-responsive rather than fixed-time. Moving car observer surveys were carried out to assess the network performance firstly with the outdated fixed-time control, then with SCOOT constrained to run according to an updated fixed-time plan, and finally with full SCOOT operation. Kerbside levels of carbon monoxide and traffic characteristics data were collected continuously. This paper presents the survey methodology, data collection procedures and the results of the statistical analysis of the data relating to carbon monoxide levels, moving car observer survey and traffic characteristics. On the whole significant benefits were achieved by updating the old fixed-time plan and these were maintained after a period of a month of SCOOT operation. SCOOT operation demonstrated a reduction in peak levels over fixed-time control.