Skip to main content

Reducing congestion while maximising safety in road construction work zones

Mike Dreznes, executive vice president at the International Road Federation (IRF) discusses road safety for work zone areas. Work zones around the world can create significant congestion and can cost society billions of dollars. Estimates in the United States alone include approximately 87,600 work zone crashes involving 37,500 injuries that result in 482 million lost hours, valued at approximately US$6.5 billion. When considering these numbers worldwide, it becomes clear that work zone safety and work zone
April 30, 2015 Read time: 6 mins
Mitigating congestion in work zones
Mike Dreznes, executive vice president at the International Road Federation (IRF Washington) discusses road safety for work zone areas

Work zones around the world can create significant congestion and can cost society billions of dollars. Estimates in the United States alone include approximately 87,600 work zone crashes involving 37,500 injuries that result in 482 million lost hours, valued at approximately US$6.5 billion. When considering these numbers worldwide, it becomes clear that work zone safety and work zone congestion represent significant costs to a global society.

Traditionally, Departments of Transportation (DOTs) and contractors have tried to use positive guidance techniques in work zones such as signs, pavement markings. Channelising devices, and in recent years automated arrow and message boards have also been used to provide clear information to guide motorists through the work zone safely. All of these positive guidance techniques are important and should continue to be an integral part of modern day work zones. As these products have evolved technology-wise, so have portable barriers and crash cushions designed to be used in work zones. Today a wide variety of portable barriers are available to meet the dynamic requirements of modern work zones on rural roads as well as in heavily congested metropolitan areas. As opposed to the traditional concrete portable barrier, this new class of moveable barrier is designed to fit the unique needs of both short and long duration projects.

In a recent webinar hosted by the International Road Federation (3918 IRF Washington) Work Zone & Temporary Traffic Control Safety Subcommittee, attendees learned about the trade-offs between mobility and safety in a work zone. Traditionally a designer had to choose safety with a concrete barrier over the flexibility of a cone or barrel that could be used to open and close lanes for traffic during construction.
For many years Lindsay Transportation Solutions has offered its flagship concrete moveable barrier as a way to open and close lanes to provide traffic management alternatives on larger work zone projects. Today other steel moveable barrier systems (2438 Lindsay, 7402 Trinity Highway Products, Highway Care, 231 Hill & Smith, 7828 Saferoads, and 782 Volkmann & Rossbach) are being deployed in both short- and long-term work zones. Since some of these newer barriers can be supplied with retractable wheels, they can be easily moved into place by hand or with lightweight equipment to provide positive protection in work zones that historically only used cones to open up the work zone.

In addition, newer, innovative, even more mobile barriers are available that provide extremely mobile short-term positive protection. These devices from 6724 Mobile Barriers LLC are perfect for specialised guardrail and bridge repair since no time is required to deploy portable barriers.

Some of these products have been available for a number of years. But in many countries, contractors are allowed to set up the work zone to their own criteria with minimal concern for motorist safety and mobility. And many contractors only do what is required regarding safety and mobility. These firms would argue that spending more money to improve safety and mobility and/or to be innovative compared to their closest competitor could lose them the project. The challenge for highway safety professionals in many countries is to implement standards and specifications that take into account the mobility needs of the motorists, as well as the safety needs for the motorists and the workers. These standards will then require contractors to use these state of the art concepts discussed earlier. Implementing some of these advanced techniques could save the road authority money because the job may be completed faster.
One method of traffic congestion mitigation is the use of ramp metering, which is typically used in large metropolitan areas that are accustomed to high traffic volumes. The idea is to break up platoons, or groupings of vehicles attempting to enter the freeway simultaneously, and to allow them to merge in a safe manner. Ultimately, this helps to spread out the overall traffic flow, resulting in decreased congestion.  

Ramp meters can take on many different form factors depending on local specifications. Most typically, ramp meters feature a two-section signal head with one red indication, and one green indication. These signals are positioned near the end of freeway on-ramps, with signage instructing drivers where to stop, and how many vehicles are permitted to proceed per green indication.

The technology behind the concept of ramp metering has advanced significantly since the 1960s, when human flaggers were used to release vehicles onto the Eisenhower Expressway in Chicago. Today, traffic sensors allow meters to adapt to real-time traffic conditions using advanced algorithms, resulting in the most efficient traffic flow. Countries across the globe have adopted the concept, from the United States to Germany, the UK to Australia. 

Recent studies have shown that ramp meters not only improve traffic flow and reduce congestion, but also have a positive impact on the overall safety of freeway driving. This is especially true in and around construction zones.  By using temporary ramp meters on freeway ramps leading up to a highway construction site, traffic congestion can be quelled before it becomes a problem.
Combining some of the newer moveable barrier products with the sensing and messaging equipment available today can help to create dynamic and safer work zones that will result in reduced accidents and congestion. European designers have used some of these smart work zone systems in the past and 3260 World Highways and ITS International have reported on them before, but they were experiments. Ministries and DOTs need to start to require these innovative concepts to make their work zones safer with increased mobility.   Many of these ministries and DOTs are already doing a good job through the use of advanced marketing and real-time information to notify communities and motorists of upcoming large work zone projects. If the next step was taken to actively manage positive protection in the work zone with moveable barriers and to use state of the art sensors and concepts like temporary ramp metering, the overall level of congestion and even the length of time the work zone is needed can be greatly reduced.

Safety and congestion in work zones are not always considered in a project bid, but they can represent a significant cost to society. If road authorities created new standards and incentives requiring contractors to use some of the innovative road safety devices discussed in this article and in the IRF webinar, the ultimate result will be a reduction in the number and seriousness of crash incidents and a reduction in traffic congestion. That is something that citizens around the world should want to see.

For more information on companies in this article

Related Content

  • Rajasthan Mega Highways boost trade, tourism
    April 12, 2012
    Rajasthan is one of the most favoured tourist destinations of India for both domestic and international traffic on account of its rich array of historical forts, palaces, art and culture. In terms of area, Rajasthan is the country's largest state. Its size and strategic location means that it is traversed by substantial traffic linking the neighbouring states to the north and south. The National Highway (NH) road corridors currently accommodating this traffic are the NH-8, NH-11, NH-12, NH-14 and NH-1
  • IRF traffic management training on investing smartly, deploying effectively
    December 19, 2014
    IRF delivers advanced traffic management training in Riyadh For the second in a series of ITS courses specially tailored for the needs of fast-transitioning economies, the IRF assembled a multi-national cast of renowned instructors who delivered five modules focusing on major mobility applications. Held from October 19th–22nd, 2014, the course was attended by over 170 transportation and engineering professionals from a wide array of public agencies, including the municipalities of Riyadh, Jeddah, Dammam, t
  • Developments in tolling technology
    February 27, 2012
    Jason Barnes reviews the last few decades and the future of tolling technology. Tolling and charging technology has evolved significantly over the last three decades and that evolution is perhaps best illustrated by reductions in or complete removal of impedances to physical progress. Once, it was customary for a driver to pull up to a barrier, make some form of cash payment to a human operative in a booth, and then wait for the barrier to be raised before proceeding. Humans were eventually complemented and
  • Improving safety for cyclists
    November 29, 2013
    New systems in development for protecting vulnerable road users - Mike Woof writes In many European countries the number of people using bicycles for commuting are increasing. This is being actively encouraged by city authorities as it offers an effective way to reduce traffic congestion, lower exhaust emissions and also improve public health. The Netherlands and Denmark have long had high percentages of commuters opting to use bicycles and other European countries are looking to capitalise on the experienc