Effect of on-street parking on traffic speeds

The purpose of this study was to collect and analyse data to determine the extent that traffic flow (notably speed) is affected by on-street parking. Similar studies were done previously on major arterial roads; this research was concentrated mainly on local streets. Ten roads in Christchurch of various widths were chosen, between 8m and 13m. Sites that had only on-street parking as the main hindrance to traffic flow were chosen, for the purpose of obtaining clear relationships.

Observed speeds were recorded at various parking demand levels and then analysed. The results showed that the vehicular speeds fell noticeably with an increase in parking levels. On average, there was approximately a 10km/h reduction in mean speeds between empty and full on-street parking levels. An even bigger effect was noted in 85th percentile speeds. The magnitude of fall in speed varied only slightly based on the road widths.

Further research, by increasing the number of sites and performing speed surveys for more parking levels at the same sites, may yield more accurate results. This may be useful for policy makers to consider the role of on-street parking as part of their local area speed management strategies.

Glen Koorey co-authored this paper with University of Canterbury Masters student Gautham Praburam and presented it at the 2015 IPENZ Transportation Conference.

Link to conference paper and poster here

cars parked on streetMean speed Parking chart


Where presented/published

2015 IPENZ Transportation Group Conference, Christchurch