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DYNAMIC HIGHWAYS Driver behavior


Magic happens I


Bob McQueen ponders the inextricable correlation between the dynamic highway and the dynamic driver


find a whole idea of Dynamic Highways quite interest- ing. It conjures up a vision of the Harry Potter movie where all the staircases are moving around at Hogwarts


– that could quite easily be in all of them, of course, but once you start your trip your destination may change! Despite this reference to young Mr Potter there really is no


magic associated with Dynamic Highways. It is simply, in my opinion, a natural evolution of the application of advanced technologies to the management of highway infrastructure. Intelligent Transportation Systems have always held out the promise of major improvement to highway operations. Our implementation of advanced traffic management, travel information and electronic payment systems on our high- ways can be very effectively supplemented by using technolo- gies to adapt the nature of the infrastructure. Transportation professionals have been aware for a long time that one of the major challenges associated with asphalt, concrete and steel highway infrastructure lies is in its inflexibility. We expect one single channel of supply to cope with a wide variation of demand over a 24-hour period. During the peak periods we expect our highway to be a high-capacity facility that deliv- ers predictable and reasonable average travel speeds. During off-peak periods we expect it to support higher-speed traffic in the safest possible manner. This is a wide range of require- ments for relatively inflexible infrastructure that may have been planned and designed 20 years ago and constructed 15 years ago. Enter the emerging application of the Dynamic Highways,


also referred to as active traffic management. Through the use of information and communication technologies we can now implement tidal flow strategies, movable barriers and part-time hard shoulder running. We can also implement variable speed limits and of course use dynamic toll collec- tion to manage the demand for a given piece of infrastruc- ture at a particular time of day. Our highways can be heavily instrumented enabling us to clearly understand the effects of our strategies and make the necessary adjustments. We can now have the kind of feedback mechanisms that control and industrial engineers have been telling us about for years.


A SHOULDER TO DRIVE ON Dynamic Highways entail the use of advanced traffic man- agement and information systems to increase the flexibil- ity of highway operations during that peek when we wish


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to maximize capacity and it is possible to open up the hard shoulder as a running lane. This assumes of course that the hard shoulder has been constructed to a suitable standard in terms of pavement and geometric engineering. During the off-peak, as the need for capacity tails off, the facility can be converted into a high-speed one with hard shoulders reintroduced as a safety feature. While there are many appli- cations of dynamic highways and active traffic management in Europe and North America, I have always been particu- larly impressed by the Dutch Government when it comes to traffic management. They have always been at the forefront of practical application of advanced technologies. I have often tried to determine the reason for this and can offer you two probable causes: sheep tracks and Philips. Like many historic European cities, Dutch cities have


evolved over a long period. Longer, in fact, than the history of the motorcar. Urban surface streets that were once sheep tracks have a different geometry than the grid-like systems featured in many US cities. Population densities also tend to be higher. These factors combine to drive a demand for world-class traffic engineering. You just do not have the space to build yourself out of trouble. The other factor that I mentioned, Philips, refers to the fact that the mighty Philips company, one of the world leaders in electronics, paid early attention to the needs of traffic management. Consequently a core of expertise was developed on the interface between electronics and traffic management. Historically the Dutch have always had a space problem and have addressed it mag- nificently with land reclamation. I would put it to you that their traffic engineers and technologists have also addressed the transportation issues related to the application of advanced technologies just as magnificently. For example the Dutch Rijkswaterstaat (Ministry of Infra-


structure and the Environment) has been a pioneer in the use of Dynamic Highways technologies. Their experts iden- tified that initial implementations of speed enforcement cameras had limited ability to influence driver behavior. The locations for each speed enforcement camera quickly became known to drivers and consequently acted as noth- ing more than an electronic speed bump, with drivers slow- ing down on the approach to the location then speeding up afterwards. This caused the reluctance to introduce Dynamic Highways because of an inability to effectively enforce speed. Understanding this they began to introduce section speed


thinkinghighways.com Vol 8 No 3 North America


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