On 7 September 2015 Council resolved to adopt most of the recommendations of the Mowbray Road West Traffic Study.
This study was carried out by consultants PeopleTrans on behalf of Council.
One of the recommendations approved by Council was for the introduction of traffic calming measures in the form of a Local Area Traffic Management in Coolaroo Road and Dalrymple Avenue. It was noted within the Council resolution that the design of the LATM Scheme “will require considerable resident consultation, and there will be considerable cost involved to construct the devices”.
The PeopleTrans Study found that Coolaroo Road and Dalrymple Avenue are key routes for locals, but are also used as rat-runs by other drivers to avoid congestion on Mowbray Road West during the morning peak period.
In September 2015 PeopleTrans were commissioned by Council to undertake the concept design of the LATM measures on Coolaroo Road and Dalrymple Avenue. These measures were aimed at addressing the concerns of local residents regarding safety by reducing speed and aggressive driver behaviour on those roads.
On 19 November 2015 PeopleTrans conducted a workshop which was attended by two residents from Coolaroo Road and two residents from Dalrymple Avenue, as well as Council officers. The primary outcome of the workshop was to reach agreement on what the LATM scheme should achieve, and the location and type of LATM devices that should be introduced. At the meeting it was agreed that there were two main types of treatment that would be appropriate for Coolaroo Road and Dalrymple Avenue. These treatments were:
Sinusoidal road humps
One lane slow points
It was recommended that these devices need to be located such that they are not too far apart, (approx. 80m) if they are to be effective in reducing speeds along the whole street. Also, different types of devices may have varying impacts when used in combination. A sinusoidal road hump differs from a watts profile speed hump in that it has a smoother curved profile at its base where it meets the road. Therefore it is less severe when vehicles drive over it. For the one way slow points the study recommended that Give Way signs be installed so that right of way be given to traffic in one direction over the other direction. This is intended to reduce conflict issues related to right of way and improve the overall safety of the devices.For both sections of Coolaroo Road, this would mean that eastbound traffic would be required to give way to westbound traffic at the slow points. On Dalrymple Avenue northbound traffic would be required to give way to southbound traffic.
The advantages and disadvantages of the sinusoidal road humps are listed below:
Effective in reducing speeds
No loss of parking as drivers will be allowed to park their car on the road hump
Sinusoidal hump has a preferred profile for cyclists compared to watts profile or flattop
Would be cheaper to construct than one lane slow points
Some increase in noise due to vehicles driving over the device, but anticipated to be within acceptable levels
The advantages and disadvantages of the one lane slow points are also listed below:
Effective in reducing speeds
Includes a bicycle bypass lane
No increase in noise
Some loss of on-street parking (11 spaces in Coolaroo Rd west, 9 in Coolaroo Rd east, 8 in Dalrymple Ave) T
here was also a 3rd option for the section of Coolaroo Road to the west of Greenlands Road. This option involved a combination of formalised parking spaces and road narrowing. However this option would result in the loss of 53 out of 76 available on-street parking spaces in this section of Coolaroo Road, so it was not considered acceptable.
In addition to the above devices, PeopleTrans also recommended a modified T-intersection where Coolaroo Road meets Dalrymple Avenue.
The PeopleTrans report found that the LATM options provided for Coolaroo Road and Dalrymple Avenue would achieve the key objective of reducing speed to below 40km/hr and improving resident amenity in these streets. It also found that the relative difference relating to speed reduction between the road humps and the slow points was marginal. The slow points would be better from aesthetic viewpoint, due to the opportunity for landscaping and the minimal noise impacts, however this needs to be weighed up against the loss of parking for this option.
That Council consult with residents for their views on the proposed introduction of;
1. Sinusoidal speed humps, or
2. One lane slow points, to determine a preferred option for traffic calming devices in Coolaroo Road and Dalrymple Avenue.