Accident nightmare at Douglas and Glenluce Drive intersection
NANUSCHKA JACKSON WRITES:
There has still not been any action on my numerous e-mails over the past 18 months or so… I am attaching pictures of our latest accident, which is the third one in the past five days. It is really getting out of hand now.
We desperately need calming traffic circles at both the Douglas Drive and Glenluce Drive intersections, as well as Douglas Drive and Kingfisher Road. Please let this be taken seriously before more lives are lost here.
A study will be undertaken to determine the feasibility of the proposal at the specific intersections. However, as background information, the JRA Traffic Engineering unit responds as follows:
Each type of control measure is justified and based on international as well as local standards contained in the SADC Road Traffic Signs Manual. The disadvantages and advantages associated with each measure have been documented extensively in research papers, all which are taken into account when a decision is taken on the most appropriate
THE JRA REPLIES:
control measure from a traffic and road safety perspective.
Roundabouts equalise the priority of all approach roads. No matter how minor the intersecting road may be, it is afforded the same priority on entry as any of the major routes. Furthermore, all vehicles must slow and take gaps on approaching the roundabout and priority cannot be given to any movement without violating the roundabout operational principles. Mini-circles, in particular, must be avoided where the major road traffic is such that it will “force” priority. If heavy main road traffic makes the minor road or rightturning traffic stop and give way, even though the circle theoretically gives the minor traffic priority, a dangerous situation arises.
Unsuitable locations for roundabouts are: 1. Where minor crossroads enter major routes. 2. In signalised co-ordinated networks where they would break up the platoon flow. 3. Where traffic signals will soon be required. As per the South African Road Traffic Signs Manual, 4-way stops must be used as an interim solution where traffic signals are warranted but funding is not yet available for the installation thereof. 4. As is the case of all intersections, roundabouts should be avoided on roads with steep slopes or where the intersection is not visible. Longer ‘flat’ areas are required for roundabouts compared with other intersection types.
Various data is collected prior to the installation of any intersection control measures. These include:
Traffic Volumes Hourly intersection approach Turning movement counts for the AM and PM peak periods
Future modelled intersection approach volumes
Future turning movement volumes for the AM and PM peak hours using pre- approved growth rates or future modelling parameters
Pedestrian and bicycle volumes by approach, if applicable
Crash Data Crash data from the JMPD accident database
Existing Geometrics The existing geometrics of the intersection being considered including gradients, available road reserve, services, sight distance, lane widths, parking lanes, shoulders and/or curb treatments, medians, pedestrian and bicycle facilities, right-of-way limits and access driveways or adjacent roadways for all approaches.
Capacity and Warrant Analysis Analysis determining the delays for all movements, approaches and overall intersection for AM and PM peak hours, both existing and future conditions, for each alternative analysed.
In order for the engineer to determine if any traffic control is necessary at an intersection, data must be examined to determine if a “warrant” is met for the particular intersection control alternative. Even if a “warrant” is met, it may not be the correct action to take for a given situation. The engineer must determine if the treatment is “justified”.
These factors could include, but are not limited to existing safety and congestion issues, future road master plans for the roadway, the spacing of nearby intersections or driveways, future anticipated traffic volumes, the distance to the nearest traffic controlled intersections, the amount of turning traffic, the breakdown and percentage of types of vehicles, the amounts of non-motorised traffic, sight distance, available right of way, available funds for construction, support of the local users. cable theft, which result in power outages.
In March this year, the city allocated an additional R6 million to the JRA through the mid-year adjustment process to enable the accelerated implementation of the No Joints Policy.
This allocation was also used to improve the JRA’s traffic light fault detection systems to improve signal timings and reduce congestion, and for security surveillance of critical intersections prone to theft of infrastructure such as cables.
Additional funding was also provided for hiring personnel, and the JRA started a process of recruiting additional traffic-light repair technicians.
In the new financial year, R45m has been allocated for the replacement of damaged cables and R30m for installation of uninterrupted power supply (UPS) units at key traffic intersections.
With the additional funding for UPS units, the JRA will be able to install UPS units at 230 high-traffic volume intersections per annum.
“I am encouraged by the JRA’s progress in tackling faulty traffic signals across the city. We are gradually turning the tide on traffic congestion within the city.
“As the new administration, we will continue to do all we can to tackle the city’s infrastructure challenges so we can create an enabling environment for strong economic growth and opportunities for all,” Mukhuba added.
Just one of the many accidents which happen at an intersection in Douglas Drive, Douglasdale.