1.          ROUNDABOUTS

 

CARREFOURS GIRATOIRES

 

 

Committee recommendation

 

That Council direct staff to consider roundabouts:

 

1.         As part of new development areas or as part of new transportation proposals complemented by a public education program.

 

2.         As an alternative to traffic control signals at existing intersections complemented by a public education program.

 

 

Recommandation dU ComitÉ

 

Que le Conseil donne instruction au personnel d’envisager:

 

1.         le recours aux carrefours giratoires dans le cadre des nouveaux aménagements ou pour des nouvelles propositions de transport et de mener parallèlement une campagne d’éducation de la population.

 

2.         l’aménagement de carrefours giratoires comme solution de rechange aux feux de signalisation à des intersections existantes, moyennant une campagne d’éducation de la population.

 

 

 

 

Documentation

 

1.                  Environmental Advisory Committee’s report dated 22 August 2007
(ACS2007-
CCV-EAC-0004).

 


Report to/Rapport au :

 

Transportation Committee / Comité des transports

 

and Council / et au Conseil

 

22 August 2007 /le 22 août 2007

 

Submitted by/Soumis par : Environmental Advisory Committee/
Comité consultatif sur l’environnement

 

Contact Person/Personne ressource: Robert Tremblay, Coordinator/Coordonnateur

City Clerk’s Branch/Direction du greffe

(613) 580-2424 x28828, rob.tremblay@ottawa.ca

 

City-wide / À l’échelle de la Ville

Ref N°: ACS2007-CCV-EAC-0004

 

 

SUBJECT:

ROUNDABOUTS

 

 

OBJET :

CARREFOURS GIRATOIRES

 

REPORT RECOMMENDATIONS

 

That the Environmental Advisory Committee recommend that Transportation Committee and Council direct staff to consider roundabouts:

 

1.         As part of new development areas or as part of new transportation proposals complemented by a public education program.

 

2.         As an alternative to traffic control signals at existing intersections complemented by a public education program.

 

 

RECOMMANDATIONS DU RAPPORT

 

Que le Comité consultatif sur l’environnement recommande au Comité des transports et au Conseil de donner instruction au personnel d’envisager:

 

1.         le recours aux carrefours giratoires dans le cadre des nouveaux aménagements ou pour des nouvelles propositions de transport et de mener parallèlement une campagne d’éducation de la population.

 

2.         l’aménagement de carrefours giratoires comme solution de rechange aux feux de signalisation à des intersections existantes, moyennant une campagne d’éducation de la population.

 


BACKGROUND

 

The mandate of the Environmental Advisory Committee (EAC) is to promote the protection, maintenance and enhancement of the environment, in the City of Ottawa, to safeguard and improve the quality of life of those who live and work in the City of Ottawa, both now and in the future.

 

As part of its 2007 Council-approved Workplan, EAC adopted the following vision:

That Ottawa becomes a recognized leader within Canada and among world capitals as a sustainable community by ensuring the integration of economic prosperity, social well-being, and environmental and ecological integrity.

 

The 2007 Workplan identified the issue of roundabouts as part of efforts to reduce vehicle emissions to ensure air quality and human health.

 

Accordingly, the following motion was adopted on June 14, 2007:

 

WHEREAS idling and accelerating cars at traffic lights are a major source of air pollution.

 

WHEREAS roundabouts are widely used in Europe, Australia and more recently in the United States.  Roundabouts are being introduced in many municipalities, including Ottawa.

 

WHEREAS roundabouts require little maintenance compared to traffic lights, require no equipment to install and maintain, and require no electric power consumption.

 

WHEREAS a public education program is needed and the consideration of a stage approach, involving consideration of only single lane roundabouts in the initial stages of this program.

 

WHEREAS roundabouts have been shown to reduce fatal and injury accidents as much as 75%.  The reduction in accidents is attributed to slower speeds and reduced number of conflict points.

 

WHEREAS roundabouts reduce emissions, delay time, and fuel consumption at the intersection.  Emissions from a stopped vehicle are about four times greater than vehicles at 10 km/hr.  Replacing traffic control signals by roundabouts have the potential to reduce carbon monoxide by about 29% and reduce fuel consumption by about 28% within the area of influence.

 

WHEREAS the Mayor of Ottawa’s Task Force on Transportation’s June 2007 Final Report entitled “Moving Ottawa” recommends to identify opportunities to implement roundabouts to help calm traffic and reduce congestion “to be started as soon as possible ideally within 12 months or less.”

 

THEREFORE BE IT RESOLVED that the Environmental Advisory Committee recommend that the Transportation Committee and City Council direct staff to consider roundabouts as part of new development areas or new transportation proposals complemented by a public education program.

 

BE IT FURTHER RESOLVED that the Environmental Advisory Committee recommend that the Transportation Committee and Council consider roundabouts as an alternative to traffic control signals at existing intersections complemented by a public education program.

 

DISCUSSION

 

In the 1950’s, traffic circles began to be replaced by more modern roundabouts.  In the 1960’s, the United Kingdom adopted a mandatory yield control of all entering traffic, channelized approaches, and appropriate geometric curve to ensure that travel speeds on the circulatory channel are less than 50 km/hr.  Roundabouts can be considered as circular intersections with specific design and control features.  Roundabouts must have the appropriate curvature to slow speeds while capable of accommodating large trucks.

 

Roundabouts are widely used in Europe, Australia and recently more and more of them are being built in the United States.  There are also several Canadian cities that have started to introduce roundabouts such as Waterloo, Calgary, Guelph, Brampton, Toronto and Ottawa.  Ottawa has a number of roundabouts with the latest one in operation at the corner of Lamira and Kilborn in the Alta Vista area.  The City of Ottawa has also some useful information posted at its website.

 

Roundabout circulation flow and safety performance are greatly affected by the geometric design.  It is a matter of determining the right design that will accommodate the traffic demand while minimizing delays, crashes and costs to all users without compromising the safety of all users (vehicle, truck, pedestrian and cyclist).  Studies have indicated that roundabout capacity is similar to traffic control signals.  The roundabout design may also reduce capacity and pedestrian crossing (pedestrians have priority over entering vehicles) may affect the entry capacity. (Ref: Roundabouts: An Informational Guide, Chapter 4, Operation, US Department of Transportation, Federal Highway Administration Publication No. FHWA-RD-00-067).  

 

On the other hand, roundabouts reduce the average idling time at traffic lights from an average of 30 seconds per vehicle to zero when the flow is uninterrupted and this reduces unnecessary vehicle emission into the atmosphere.  Tony Redington conducted a study on modern roundabouts and he suggested that 25 roundabouts replacing existing traffic signals in the city of Burlington, Vermont would equate to over 20% of that City’s goal of bringing greenhouses gas emissions to 10% below the baseline 1990 level (Modern Roundabouts, Global Warming, and Emissions Reductions: Status of Research, and Opportunities for North America).

 

Benefits

 

Roundabout safety performance is directly affected by geometric design characteristics.  The design must allow traffic to slow down to enter the roundabout while accommodating all types of traffic (vehicle, truck, pedestrian and cyclist).  Roundabouts can reduce the number of major traffic accidents at intersections by forcing vehicles to slow down and reducing the number of conflicting points at which vehicle paths cross.  Roundabouts should be designed so that the speed of all vehicles is restricted to 50km/hr or less within the roundabout.  The low speeds allow drivers more time to react to unexpected conflicts.  To achieve this safety advantage, roundabout must have an adequate curvature.  There are safety benefits for pedestrian crossing, as long as pedestrians use the marked crossing where they have priority.  It remains that crossing at a roundabout is a challenge for visually impaired people.

 

A roundabout is a good way to increase the capacity of an intersection and may be preferable to stop signs or traffic lights.  It requires little maintenance compared to traffic lights and will still manage traffic flow during power outage.  There is no signal equipment to install and maintain, and no electric power consumption.

 

Roundabout can be used to reduce vehicle delay time at intersections.  By reducing vehicle idling time and stop, the roundabout will cut down on vehicle emissions and reduce fuel consumption. Roundabouts reduce also significantly the noise level at intersections since there are fewer starts from a dead stop. 

 

A study done by Maxime Hesch examined the data when traffic lights were replaced by a roundabout at an intersection (Quantitatively Determining the Emissions Reduction Benefits of the Replacement of a Signalized Intersection by a Roundabout).  The empirical data showed that there is a 16.36% reduction in nitrous oxide and a 26.05% reduction in hydrocarbons compared to the traffic signal.  Another study referred to work done by Varhelyi in Sweden found that replacing a signalised intersection with a roundabout resulted in an average decrease in carbon monoxide (CO) by 29% and oxides of nitrogen emissions (NOx) by 21 % and fuel consumption by 28% per car within the influence of the junction (Ref: Impact of Modern Roundabouts on Vehicular Emissions, Srinivas Mandavilli, Eugene R. Russel and Margaret J. Rys, Proceeding of the 2003 Mid-Continent transportation Research Symposium, Ames, Iowa, August 2003).  Therefore, roundabouts reduce greenhouse gas emissions from the transportation group.

 

With a roundabout, the centre island offers an opportunity for landscaping which can be pleasing to the eyes by enhancing the appearance of the intersection.

 

Education

 

Considering the limited number of roundabouts in North America, it is important to educate the public on their use and rules.  Drivers, pedestrians and bicyclists that are using roundabouts must understand traffic rules.  Acceptance of roundabouts will increase when the public is educated and has a clear understanding on how to use them.  The education component must focus on how to use roundabouts for all users.

 

Building roundabouts without having an education element will only increase public dissatisfaction with such an initiative.  Road safety can also become an issue if people are unsure how to navigate through roundabouts.  The City is encouraged to continue with the gradual introduction of roundabouts supported by an aggressive education program.  The education should also be provided to students since many of them are pedestrians.

 


Identification of Opportunities

 

The implementation of roundabouts needs to identify opportunities for doing so.  In new communities or development areas, roundabouts should be incorporated in the transportation plan from day one.  When planned as part of a community development, there is no additional cost in building roundabouts.  Roundabouts have much lower operating costs than traffic signals.

 

For existing intersections, roundabouts should be considered when problems have been identified, such as safety or capacity problems that demand changes to the intersection.  In such a situation roundabouts should be considered as one of the potential solutions.  In addition, roundabouts should be considered when entire streets are being ripped up for new sewer lines.  Roundabouts are often a preferred solution over other traffic control options for conditions such as:

 

a.   Intersections with a high percentage of turning movements;

b.   Intersections with high traffic volumes at peak hours but relatively low traffic volumes during non-peak hours;

c.       Existing two-way stop-controlled intersections with high side-street delays (particularly those that do not meet signal warrants) intersections that must accommodate U-turns;

d.   Intersections at a gateway or entry point to a campus, neighbourhood, commercial developments, or urban area;

e.       Intersections where a community enhancement may be desirable;

f.        Intersections or corridors where traffic calming is a desired outcome of the project;

g.   Intersections where widening one or more approach may be difficult or cost-prohibitive, such as at bridge terminals;

h.   Intersections where traffic growth is expected to be high and future traffic patterns are uncertain (factor that is more likely applicable to new communities);

i.         Locations where the speed environment of the road changes (for instance, at the fringe of an urban environment);

j.    Locations with a need to provide a transition between land use environments (such as between residential and commercial uses); and

k.   Roads with a historical problem of excessive speeds (roundabouts are designed to force drivers to slowdown).

 

Conclusion

 

There is recognition by many cities across Canada and the United States that roundabouts can be useful in managing traffic flow while providing a number of benefits.  While roundabouts can contribute to improvement in overall safety performance, another benefit often overlooked is the reduction in greenhouse gases from idling (average of 30 seconds) and accelerating vehicles.  A well-designed roundabout will keep traffic moving, will reduce unnecessary stops and will improve intersection appearance.

 


CONSULTATION

 

Public Works and Services

 

Staff support the consideration of roundabouts and have implemented several over the past number of years.  Modern roundabouts are already being considered as an alternative to the installation of new traffic control signals, and the development community have been encouraged to consider roundabouts as part of their plans for new development areas.  Staff agree with the need for ongoing public education to help build public understanding and acceptance.

 

As a clarification, in Ontario, as with most North American provinces and states, the Highway Traffic Act does not include any specific operating procedures for roundabouts.  Of particular note in Ontario, pedestrians do not have priority at marked crosswalks unless accompanied by a traffic control device, including at roundabouts.

 

As a further clarification, while roundabout-controlled intersections require substantially less power consumption than those controlled by traffic signals, with the need to ensure appropriate intersection lighting levels, to light objects and conflict areas where pedestrians and bicyclists may be present, roundabout controlled intersections still involve some level of power consumption for streetlighting.

 

The approach taken in Ottawa regarding the use of roundabouts has been to concentrate initially on single-lane roundabouts, in order to build public understanding and acceptance.  It is generally much easier for the public (motorists, cyclists and pedestrians) to understand the rules of the road for a signal lane roundabout as compared to a multi-lane roundabout.  As city-wide public understanding and acceptance increases, multi-lane roundabouts along major collector and arterial roads will also be considered as a potential alternative to traffic control signals.

 

Further information regarding roundabouts in Ottawa can be found at Ottawa.ca, through the link “Ottawa on the Move”.

 

Planning, Transit and the Environment

 

Staff in PTE support the use of roundabouts for their environmental benefits, specifically the reduction in greenhouse gas and other emissions, resulting from the reduction in vehicle idling and the reduction of electricity consumption. Pedestrian travel must be accommodated safely.  A number of Community Design Plans currently in development are exploring the use of roundabouts.

 

FINANCIAL IMPLICATIONS

 

Any impacts such as pressure or benefits of roundabouts implementation would be submitted with future Operating and Capital submissions, or result through a development agreement requirement.  One potential cost benefit could be the elimination of traffic control signal Capital costs and annual Operating costs.  However the net benefit on the capital side in not constructing a signalized intersection is dependent upon the costs to construct the roundabout.

 

As an example provided by Traffic & Parking Operations, the cost to construct a roundabout depends on the extent of construction, whether or not the acquisition of property is required or if utilities need to be relocated.  The experience to date along two lane roadways that require only a single lane roundabout is that actual costs to construct the roundabout are in the range of $600,000 to $700,000.  By comparison, a new traffic control signal installation with left-turn lanes on all approaches can cost approximately $650,000.  Where no roadway modifications are required, new traffic control signals costs are often much lower, in the range of $150,000.   There are annual maintenance and operating cost associated with operating the traffic control signal, averaging about $6,800 per signal location.  In older more established communities, there may not be sufficient room for constructing a roundabout, without the purchase of additional property, at additional cost. 

 

DISPOSITION

 

Planning, Transit and the Environment staff to consider roundabouts in new areas and Public Works and Services staff to consider the use of roundabouts as an alternative to traffic control signals in existing areas or as part of new transportation proposals.