Austroads (2004) promotes speed based design when installing LATM's and states that "there is very little systematic information available on device crossing speeds; there is even less reliable information on whether or not 'operating speeds' can be given for a given type of device". This research investigates the effectiveness of traffic calming devices on local roads in New Zealand, and compares the installation criteria and the resultant effects with the findings sourced from a literature review and complements work undertaken by the LTSA (2004) who recommended that: a.A set of guidelines on traffic calming devices should be developed. b.RCA's should assess the effects of the traffic calming devices. c.Its Standards and Guidelines Steering Group, should develop a set of case studies to evaluate the overall effect of various types of traffic calming devices. The findings of the literature review was that: •Traffic calming devices must only be installed after considering the resultant effects, e.g. traffic volumes, speed, noise, vehicle type, community attitudes, vibration and comfort. •Several devices conclusively reduce speed, and can be used without undertaking further analysis, i.e. raised tables, road humps, road cushions, slow points and perimeter threshold treatments. •Limited information exists within New Zealand that can be readily accessed and the author has been unable •to conclusively demonstrate their effectiveness in reducing speeds, i.e. centre blisters, kerb extensions, •parking; mid-block medians, reduced lane width and carriageway narrowing. •Several websites exist overseas with useful information. The findings of the case studies was that: •Of the 21 schemes, 10 resulted in a statistically significant reduction in speed, while 2 resulted in a statistically significant increase in speeds. •The majority of devices that have been installed have not always being installed in accordance with the findings of the literature review. •Many RCA's install traffic calming devices without monitoring the resultant effects. •The turnover in staff and lack of record keeping means that the industry as a whole is not learning, a situation compounded by no central database existing and being maintained. •The spacing of devices often exceeded recommended guidelines. It is recommended that: •Land Transport develops a design guide focusing on the devices that conclusively reduce speed and the resultant effects. •Further research is undertaken into the community acceptability of devices. •A design guide is produced for new developments, in order to avoid storing an LA TM at a later date. •A 'traffic calming' website and discussion group should be set up similar to the ITE website.
展开▼
