Managing traffic requires being able to detect a variety of vehicles characteristics in different circumstances, for different purposes: traffic flows, volumes, speeds and vehicle types for planning and design; detecting incidents for emergency response; flows on ramps for metering; vehicle volumes approaching intersections for signal timing and control; and traffic conditions for traveller information are some examples.
Can advances in intelligent vehicles help?
Developments in intelligent transport systems, particularly transmission of real-time information between vehicles (vehicle-to-vehicle), and with road network operators (vehicle-to-infrastructure), have led to consideration of further applications to deliver critical road safety and mobility outcomes.
Despite the advances made since the 1970’s, communities are demanding further improvements in road safety, reductions in the growing impact of congestion on mobility and reliability of travel, and reductions in energy use and emissions due to road transport.
I-95 Corridor Coalition TMC Simulation
The I-95 Corridor Coalition is an alliance of transportation agencies, toll authorities, and related organizations, from the State of Maine in the northeast right down the US to the State of Florida in the south.
The I-95 Corridor Coalition offers several web-based courses. In the TMC Simulation Program, you act as a TMC operator.
Due to the variety of technologies used in different Traffic Management Centers, there are two different simulation areas. The operator in the High-Tech TMC uses a Traffic Monitoring System to manage resources like a computer automated dispatch System, CCTV, pager system, dynamic or variable message signs, pavement weather sensors, traffic detectors, etc.
Monitoring and modelling travel time reliability
The use of reliability of trip arrival times does not normally form part of network performance monitoring and modelling. Reasons to monitor and model reliability of trip times include:
(a) monitoring the performance of road network;
(b) monitoring the performance of public transport networks and services; and
(c) evaluating future options.
Although some national guidelines point the way regarding reliability valuations (UK, New Zealand and Australia), current practice is somewhat lagging behind recommended approaches. There is considerable evidence from stated preference survey results related to demand estimation for toll roads and public transport projects, that traveller’s willingness to pay, extends to reliability of travel time, especially for time-sensitive trips.
Freeway Service Patrol returns high benefit
A research study found that a Virginia DOT Freeway Service Patrol (FSP) provides a 4.7 to 1 benefit-cost ratio.
The Hampton Roads FSP, which consists of 48 vehicles and operates 24/7 on 80 miles of interstate highway, responded to 40,700 incidents during the 12-month period evaluated.
The patrols aim to reduce congestion, improve safety and customer service. Other benefits include reduced secondary incidents, increasing safety and saving additional delays.
Congestion … funding … congestion … funding
Debate in the US has focussed on the need to find considerable additional funding to meet the needs for a congested transport system.
The National Transportation Policy and Revenue Commission, set up by the Federal Government, published their report Transportation for Tomorrow on 15 January 2008.
Interestingly the Commission of 12 ended up with three different views: the report, supplementary views and a minority report. So it appears that there is no easy, clear answer, even fora Commission specially set to answer the questions raised.
Virtual Incident Management Training
The University of Maryland’s Center for Advanced Transportation Technology Laboratory (CATT Lab) is working with the I-95 Corridor Coalition to create virtual incident management training software program.
An intensive training program is being developed that will use three-dimensional, multi-player computer gaming simulation technology and distance-based learning technologies to test, validate, certify, and reinforce the dissemination of best incident management practices.
The program will present typical incident situations and allow the participants to play out their normal roles in what is essentially a highly structured and recorded video game.
Benchmarking Traffic Incident Management in Australia
To identify potential innovative practices that may be suitable for wider application, as well as provide a benchmark for ongoing improvement, a review of current traffic incident management (TIM) practices in major urban regions across Australia was undertaken in 2005-6. The review covered current traffic incident management practices in Sydney, Melbourne, Brisbane, Adelaide and Perth.
The assessment, modelled on the self-assessment approach taken by the US Federal Highways Administration approach, covered program and institutional issues (strategy and programs, resourcing, performance measurement, institutional arrangements), operational issues (procedures for major incidents, responder and motorist safety, response and clearance policies and procedures) and communication and technology issues (integrated inter-agency communications, transport management systems & traveller information).
Dealing with Uncertainty in Travel Demand Forecasting
Sources of error
When forecasting for the medium to long term we need to be clear in acknowledging that we are dealing with an uncertain future. There are a number of factors which may contribute to errors and uncertainty in forecasts. Sources of uncertainty when forecasting travel demand include:
Demographic and socioeconomic input data: employment and population market segments; economic activity: impacts on drivers for freight and passenger demand.
Assumptions about physical networks (base year and future projects): observed counts may affect model calibration and validation; road and public transport network assumptions.
Values of travel time (VTT): strategic transport models use an imputed VTT for each main trip purpose. VTT are usually estimated from the coefficients of mode choice models.
Time of day effects: factors are usually used for different time periods, (peak, daily, weekly, monthly, and annually), based on historical data. Such factors will not deal with peak spreading or mixes in the traffic composition. Methods to model time-of-day choice explicitly are beginning be implemented in practice.
Optimism bias: Use should be made of strategic transport models to investigate the impact of proponent optimism bias on overall results. Patronage optimism bias should be examined using sensitivity testing.
Traffic Incident Response Practices in Europe
The U.S. Federal Highway Administration released a report that includes recommendations to improve traffic incident response in the United States.
The recommendations are based on an April 2005 scanning tour on traffic incident response practices, procedures, and technologies of England, Germany, the Netherlands, and Sweden that assessed and evaluated various practices for responding to traffic incidents.
The recommendations are organised under the three primary themes of programs and institutions, tactical and on-scene management, and communications and technology.