Traffic Demand Management at JunctionsP.G.Dasun RansiriBscC-550/09-03/0021CINEC Maritime Campus
Traffic Demand Management…Transportation demand management, traffic demand managementor travel demand management (all TDM) is the application ofstrategies and policies to reduce travel demand (specifically that ofsingle-occupancy private vehicles), or to redistribute this demand inspace or in time
Junction………. A junction, when discussed in the context of transport, is a location where traffic can change between different routes, directions, or sometimes modes, of travel.
Why Management of TrafficDemand at JUNCTIONS isImportant….??? Both Traffic Demand Management & Junction are two separate broad areas which need expertise knowledge & skill to handle according to their definitions previously discussed….. But Traffic Demand Management @ Junction ……?????????
Negative Impacts of Failure toManage Traffic Demand at Junctions Very high rate of accidents and fatalities Environmental Pollution Wasting Money and Time Health Problems Lack of public and safe transport The environmentally friendly ways of travelling are exposed to higher risks than the environmentally malign ones
Methods which can be employed for Traffic Demand Management at Junctions….1) Traffic Surveys & Information Gathering2) Educate and Inform Public3) Enforcement of traffic laws and regulations4) Junction Improvementv. Road Signsvi. Flyovervii. Traffic lightsviii.Pedestrian Crossingix. Bicycle-friendly traveling10) Pricing11)Active traffic Management (ATM)12)Integrated Demand Management (IDM)
• Traffic Surveys & Information Gathering Information gathering is essential element in traffic studies. Modern technology & specialized equipment can be used. Gathered information should be properly analyzed Survey Reports should be presented to relevant authorities & public
Extracting Traffic Parameters at Intersections Through Computer Vision By K.D. Peiris and D.U.J. Sonnadara Department of Physics, University of Colombo Automation of Traffic Flow Measurement Using Video Images By G. C. de Silva Department of Computer Science and Engineering University of Moratuwa Sri Lanka
1) Educate and Inform Public •Public should be properly educate & informed •Use of Modern technology, expertise skills •Feedback & Suggestions should be efficiently gatheredI.Use of ICT (Social Network)
• Travel plan- [green travel plan] A travel plan is a package of actions designed by a workplace, school or other organization to encourage safe, healthy and sustainable travel options. By reducing car travel, Travel Plans can improve health and wellbeing, free up car parking space, and make a positive contribution to the community and the environment. Every Travel Plan is different, but most successful plans have followed a structured process in their development. These travel Plans should be properly communicated to pubic.
• Enforcement of traffic laws and regulations The enforcement of traffic laws and regulations can achieve significant traffic flow improvements. Improved safety is often an important outcome of enforcement. Proper enforcement is best implemented when the traffic code is clear and traffic management measures support desirable driving behavior.
• Junction Improvementi. Road SignsTraffic signs or road signs are signs erected at the side of roads to provide information to road users. With traffic volumes increasing over the last eight decades, many countries have adopted pictorial signs or otherwise simplified and standardized their signs to facilitate international travel where language differences would create barriers, and in general to help enhance traffic safety. Such pictorial signs use symbols (often silhouettes) in place of words and are usually based on international protocols.
• Flyovers (Overpass) An overpass /flyover is a bridge, road, railway or similar structure that crosses over another road or railway. An overpass and underpass together form a grade separation.
i. Traffic lights Traffic lights, which may also be known as stoplights, traffic lamps, traffic signals, stop-and- go lights, are signaling devices positioned at road intersections, pedestrian crossings and other locations to control competing flows of traffic.
Queue Interactions ……. Queue Interactions look at how queues can reduce capacity through spillback, starvation, and storage blocking between lane groups. Spillback Spillback is caused when a queue from a downstream intersection uses up all the space on a link and prevents vehicles from entering the upstream intersection on green.
Starvation Starvation occurs when a downstream signal is green, but the signal can not service at full capacity efficiency because the upstream signals is red
Storage Blocking Storage Blocking occurs when queues extend past the opening of the storage bay. Through traffic can block access to the left or right storage bay, or turning traffic can use up the bay space and block through traffic. Figure illustrates storage blocking of left traffic by through traffic. The left turning vehicle is blocked from the left storage bay by through traffic. The signal shows a green left arrow, but no left traffic can reach the stop bar. Storage blocking is a combination of spillback and starvation. In this case the through traffic is causing spillback. The left movement is experiencing starvation because of the spillback.
• Pedestrian Crossing A pedestrian crossing or crosswalk is a designated point on a road at which some means are employed to assist pedestrians wishing to cross. They are designed to keep pedestrians together where they can be seen by motorists, and where they can cross most safely across the flow of vehicular traffic. Pedestrian crossings are often found at intersections, but may also be at other points on busy roads that would otherwise be too unsafe to cross without assistance due to vehicle numbers, speed or road widths.
• Bicycle-friendly traveling "Bicycle-friendly" describes policies and practices which may help some people feel more comfortable about traveling by bicycle with other traffic. The level of bicycle-friendliness of an environment can be influenced by many factors resulting from town planning and cycling infrastructure decisions.
• Pricing Congestion pricing or congestion charges is a system of surcharging users of a transport network in periods of peak demand to reduce traffic congestion. Examples include some toll-like road pricing fees, and higher peak charges for utilities, public transport and slots in canals and airports. This variable pricing strategy regulates demand, making it possible to manage congestion without increasing supply. Delay-based road pricing is the policy of charging drivers based upon the amount of time they spend queuing. Delay- based pricing, whatever its other effects, is an extremely efficient way of causing drivers to avoid congested routes. Too much delay-based pricing leads the drivers onto inefficient routes since they are travelling a large extra distance to avoid the delays.
Reference Congestion management and electronic road pricing in Singapore This paper details the experience of Singapore and the effort made to curb vehicular increase on the roads using a state-of-the-art regulated Electronic Road Pricing (ERP) scheme. By Faculty of Business Administration, National University of Singapore, 15 Law Link, Singapore 117591, Singapore
• Active traffic Management (ATM) scheme combines a number of new technologies and existing motorway features to provide:• Reliable journey times• Reduced congestion• Enhanced information to drivers• Quicker response times to incidents
How will Active Traffic Management bedifferent? Driver information signs Speed limit signals Emergency refuge areas New emergency roadside telephones Hard shoulder running between junctions if necessary New congestion and incident management systems
• Integrated Demand Management (IDM) •seeking to address congestion problems, there is a need to make better use of existing capacity. •Better manage both the strategic road network and local road network, with the ultimate aim of having a network that operates in balance IDM seeks to manage both road networks together to improve the end to end journey experience for the road user, irrespective of which network they are using Aiming to manage both road networks as one, the concept of IDM focuses on using existing technology and traffic measures on both networks.
Case Study- MUSIC (Management of traffic Using Control) In three cities, network models have been used to create fixed-time signal settings, which attempt to meet the traffic demand management goals of the city authorities. Urban Traffic Control (UTC) can have a significant effect on driver route choice but practical applications for this have been limited. MUSIC project aims to demonstrate a range of possibilities for traffic demand management (TDM) measures which can be implemented using a cities’ existing UTC system. The project uses a specially developed software model known as STEER (Signals/Traffic Emulation with Event-based Responsiveness) to produce fixed-time signal timing plans
The MUSIC method is a combination of Smith’s policy- signals can attempt to route vehicles onto roads which have greater capacity by giving more green time to routes with greater capacity Virtual delay-based road pricing- policy of charging drivers based upon the amount of time they spend queuing.
The ideas of P0, a policy which favors high saturation flow routes, and delay-based pricing which forces drivers onto more efficient routes leads to the MUSIC method:1. Impose a delay-based pricing on the simulated network with a small price p. This should force drivers onto optimal or nearly optimal routes.2. Adjust signals according to P0. The signals are now weighted to give greater green to these nearly optimal routes.3. Freeze the signals and remove the pricing. Allow the vehicles to return to an un-priced user equilibrium. This will provide an assessment of the signal timing plan created in step 2.4. Increase price p and go to step 1. Repeat until an optimal pricing level p has been located by examination of the total travel time on the network at the end of step 3.
Practical application in Sri Lankan scenario…. T raffic demand management schemes should be designed to deal with countries unique traffic flow characteristics. Low cost and quickly implemented schemes catering to the specific needs of each vehicle type, including NMVs and pedestrians, are needed.
C o n c l u s i o n ….In urban road networks, the junctions are thedeterminants of road network capacity. Gradejunctions also play an important role inproviding safe pedestrian road crossing.Traffic delays at junctions contribute greatly toair pollution because the emission rates (foralmost all pollutants) of idling vehicles aremuch higher than at free flow. Well-designedjunctions that support modern traffic signalcontrol systems can minimize delays andtraffic stoppages and so, r e d u c ee mis s io n s .