Who is on first?

The influence of policy and institutional issues which influence day-to-day operations, also drive the choices of technology used in the sequence of events that make up incident response and can be a barrier to success.

Optimising capacity of a road network through traffic incident management is a key strategy to managing congestion. With the realisation that it is not feasible or affordable to build our way out of congestion has come an interest in finding smarter ways of maintaining a given level of service.

However, congestion management may not be a core issue for all organisations involved in network operations and incident management. Public safety agencies are concerned about collecting evidence and fire and rescue cultures have a strong worker safety bias - and getting traffic moving is not a primary objective.

Evolving roles
Many road and traffic agencies are evolving from being solely a road asset manager, to becoming a network operator and taking on responsibility for traffic management, with the specific aims of improving journey time reliability and safety and reducing the impact of roads on the environment.

Previously, that meant most of the investment tended to go into improving the asset, not how it was operated, now there is renewed interest in investments in procedural or network operational areas. Incident management also involves multi-agency stakeholders.

This requires the alignment of stakeholder priorities and responsibilities, aiming to embed business drivers to ensure a common direction. An example is the adoption of an open roads or quick clearance policy a regional level. Then responders within diverse stakeholder organisations need to be fully aware of both their roles and those of others.

Incidents and congestion
A large proportion of congestion (see Cost of Traffic Incidents), particularly non-recurrent congestion, is incident-related. Faster, more effective incident response can therefore have a major impact on improving journey reliability.

In the event of a serious collision police will want to investigate thoroughly just what has gone on as there may be a potential criminal investigation, and the longer the investigation takes the worse the congestion which results can be.

There is technology available which can significantly reduce the time taken to carry out crash investigations and re-open the road, but there is little incentive for the police to invest in it because it doesn’t align with their key objectives.

In a number of jurisdictions the road agency has taken a lead role in championing new technology and procedures, advocating the benefits and assisting with funding or building the case for shared funding.

Quick clearance is the key to success in incident management but each organisation involved in managing and operating roads needs to be clear as to what its responsibilities are and what the others are doing.

For traffic incident management to be successful involves policy and institutional alignment:

1. alignment of responder agency core objectives
2. having incentives to drive organisational behaviour, such as key performance measures that are regularly reported and
3. a clear understanding by all on the benefits of quick clearance.

Cost of Traffic Incidents

Large urban areas are facing an increasing challenge of mobility (congestion), safety and environmental impacts due to traffic incidents.

Traffic incidents are estimated to account for about 25% of traffic congestion and bad weather another 15% (FHWA 2007). Hence congestion due to traffic incidents and bad weather can be as much as 40% of the total congestion.

Traffic incidents can have significant impacts on road users and the community. Injured people need to be recovered quickly from crashes and the potential for secondary incidents needs to be avoided. The safety or emergency responders and traffic controllers are at risk in moving traffic conditions.

Traffic delays result in lost time, schedule disruptions for public transport, financial costs for freight operators and local businesses and increases in vehicle emissions due to idling traffic.

While people can factor in “normal” congestion as part of their commute, unexpected congestion can make people late for work, meetings, appointments, or other activities.

Alternatively, people may choose to leave early in case they run into unexpected traffic, meaning they also may arrive earlier than necessary. A reduction of one minute of travel time under unexpectedly congested conditions is valued at over 2.5 times the value of one minute of time under normal condition (Small et al 1999).

Typical Impacts of Traffic Incidents

• Regional Impacts: Diminished cost competitiveness and market growth opportunities lead to a reduced ability to retain, grow, and attract business. Increased emissions and energy use.
  
  
• Freight Impacts: Longer travel times and less reliable delivery times. To compensate typically add vehicles and drivers and extend their hours of operation, eventually passing the extra costs along to consumers.
  
  
• Business Impacts: Increased cost of delivering goods and services, costs of spoilage for time-sensitive, perishable deliveries and maintaining greater inventory to cover the undependability of deliveries.
  
  
• Household Impacts: As travel time and vehicle operating costs increase and reliability and mobility decrease, then the quality of life is diminished.
  
  
• Agency Impacts: Additional cost of responders, equipment and materials – overtime, equipment hire, clean up etc (opportunity cost). Increased exposure to occupational health and safety hazards from passing traffic, hazardous materials, etc
  
  
• Road User Impacts: Exposure to secondary incidents from end of queue (high speed differentials), distraction (especially at speed), etc

Quick clearance of traffic incidents can greatly assist in the reduction of traffic congestion through minimising traffic delays, reducing the number of secondary crashes that occur and decreasing vehicle emissions.

References:
FHWA (2007) Traffic Congestion and Reliability: Trends and Advanced Strategies for Congestion Mitigation Strategy to Reduce Congestion, Federal Highways Administration, Washington DC.

Small K, Noland R, Chu X and Lewis D (1999) Valuation of Travel Time Savings and Predictability in Congested Conditions for Highway User-Cost Estimation, National Cooperative Highway Research Program Report 431, Transportation Research Board, Washington.