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A series of chassis dynamometer test trials were\ud conducted to assess the performance of a Fourier\ud Transform Infra Red (FTIR) system developed for\ud on-road vehicle exhaust emissions measurements.\ud Trials used a EURO 1 emission compliant SI passenger\ud car which, alongside the FTIR, was instrumented to\ud allow the routine logging of engine speed, road speed,\ud throttle position, air-fuel ratio, air flow and fuel flow in\ud addition to engine, exhaust and catalyst temperatures.\ud The chassis dynamometer facility incorporated an\ud ‘industry standard’ measurement system comprising\ud MEXA7400 gas analyzer and CVS bag sampling which\ud was the ‘benchmark’ for the evaluation of FTIR\ud legislated gas-phase emissions (CO, NOx, THC and\ud CO2) measurements.\ud \ud \ud Initial steady state measurements demonstrated strong\ud correlations for CO, NOx and THC (R2 of 0.99, 0.97\ud 0.99, respectively) and a good correlation for CO2 (R2 =\ud 0.92). Subsequent transient and total mass emissions\ud measurements from replicate samplings of four different\ud driving cycles (two standard cycles, FTP75 and NEDC,\ud and two novel cycles based on real-world data collected\ud in Leeds) also show good response of FTIR and\ud satisfied agreement between the FTIR and CVS bag\ud sampling measurements.\ud \ud \ud In general, the trial results demonstrate that the\ud on-board FTIR emission measurement system provides\ud reliable in-journey emissions data.

The objective of this work was to determine the effect of\ud one form of traffic calming on emissions. Traffic calming\ud is aimed at reducing average vehicle speeds, especially\ud in residential neighborhoods, often using physical road\ud obstructions such as speed bumps, but it also results in\ud a higher number of acceleration/deceleration events\ud which in turn yield higher emissions. Testing was\ud undertaken by driving a warmed-up Euro-1 spark ignition\ud passenger car over a set of speed bumps on a level\ud road, and then comparing the emissions output to a noncalmed\ud level road negotiated smoothly at a similar\ud average speed. For the emissions measurements, a\ud novel method was utilized, whereby the vehicle was\ud fitted with a portable Fourier Transform Infrared (FTIR)\ud spectrometer, capable of measuring up to 51 different\ud components in real-time on the road. The results\ud showed that increases in emissions were much greater\ud than was previously reported by other researchers using\ud different techniques. When traffic-calmed results were\ud compared to a smooth non-calmed road, there were\ud substantial increases in CO2 (90%), CO (117%), NOx\ud (195%) and THC (148%). These results form the basis\ud for a good argument against traffic calming using speed\ud bumps, especially for aggressive drivers. Slowing traffic\ud down with speed restrictions enforced by speed\ud cameras is a more environmentally friendly option.

Intelligent Speed Adaptation (ISA) systems use in-vehicle electronic devices to enable the speed of vehicles to be regulated externally. They are increasingly appreciated as a flexible method for speed management and control, particularly in urban areas. On-road trials using a small numbers of ISA equipped vehicles have been carried out in Sweden, the Netherlands, Spain and the UK. This paper describes the developments made to enhance a traffic microsimulation model in order to represent ISA implemented across a network and their impact on the networks. The simulation modelling of the control system is carried out on a real-world urban network, and the impacts on traffic congestion, speed distribution and the environment assessed. The results show that ISA systems are more effective in less congested traffic conditions. Momentary high speeds in traffic are effectively suppressed, resulting in a reduction in speed variation which is likely to have a positive impact on safety. Whilst ISA reduces excessive traffic speeds in the network, it does not affect average journey times. In particular, the total vehicle-hours travelling at speeds below 10 km/hr have not changed, indicating that the speed control had not induced more slow-moving queues to the network. A significant, eight percent, reduction in fuel consumption was found with full ISA penetration. These results are in accordance with those from field trials and they provide the basis for cost-benefit analyses on introducing ISA into the vehicle fleet. Contrary to earlier findings from the Swedish ISA road trials, these network simulations showed that ISA had no significant effect on emission of gaseous pollutants CO, NOx and HC. Further research is planned to investigate the impact on emission with a more comprehensive and up to date modal emission factor database.