Too much safety can be dangerous

    The Sunday of September 3, 1967 was a special day for Swedes. From one o’clock at night until six in the morning all road traffic was suspended, except for emergency vehicles, and even these had to follow special regulations. Between 4:30 and 5:00 am, all the roads in Sweden received a drastic makeover. That Sunday, Swedes switched from driving on the left-hand side of the road to the right.

    Planning this important change in Sweden had taken several years. In 1955 there was even a referendum in which more than 80% of voters opted against switching sides. However, despite the will of the people, the expert and practical arguments were too convincing to allow Swedes to continue driving “the English way”. What contributed most to the decision was the fact that, in all the neighboring countries, people drove on the right lane. In addition, most of the cars in Sweden already had a left-sided steering wheel, so it was just a matter of time before the decision to switch the direction of driving was taken.

    Contrary to expectations, the great change of traffic regulations that took place in Sweden on “H-Day” (H for the Swedish höger, meaning “right”), as that first Sunday of September 1967 was named, did not result in a higher number of traffic accidents. Quite the opposite, in fact: on the Monday after the new regulations were implemented, the number of accidents recorded was actually lower than the daily average up to that time. It took a whole year until the average number of car crashes rose back to that seen before “H-Day”.

    The paradox of perceiving safety

    In his book Traffic: Why We Drive the Way We Do and What it Says About Us (Allen Lane, 2008), one of the questions Tom Vanderbilt asks himself is how an actual increase of danger on the road, like that which took place in Sweden in 1967, can decrease the number of accidents. The answer is, of course, quite simple: upon changing the side of the roads on which they drove, people felt less safe and therefore drove more carefully. After a year’s time, when they became used to the new regulations, they became more confident in their driving again and the number of accidents rose back to the previous level.

    On the basis of additional examples, Vanderbilt concluded that in perceiving road danger we face a paradox: “The system that the majority perceives to be more dangerous is in fact safer, while the system that seems safer is actually more dangerous.”

    The explanation of this paradox is that people adjust their road behavior according to the feeling of risk or danger involved. If they perceive something as dangerous they will naturally be more careful than when they feel that nothing bad can happen to them. When, for example, a traffic light turns green, most drivers feel that, at least for a few moments, they own the road ahead and do not need to think about anything but stepping on the gas pedal. If a road is constructed like a racetrack the people using it will accelerate and drive faster even if there are speed limit signs on the side, because such a road makes them feel safe. Similarly, people who drive to work along the same road each day drive much faster than tourists taking the same route for the first time, which is completely understandable, as locals know every detail of the way and therefore feel much safer.

    There are several approaches to planning and building roads. According to a theory of “passive security”, roads should be built in such a way that potential mistakes made by drivers would not cause severe consequences. This way of building could be called “the engineering approach” as it tries taking into account in advance the potential errors made by drivers, much as builders and architects must consider the possibility of an earthquake or violent winds. The problem with this approach is that it does not take into consideration one major difference between an earthquake and a dangerous driver. The earthquake does not “know” that people have begun building more solid structures, so it will not become more violent than it might have been in the days before “earthquake-proof” buildings. Drivers, however, are less reliable than earthquakes in this respect. They tend to feel much less threatened on “safely” built roads, and so drive less cautiously. This in the end, can result in even more accidents than on roads which seem much more dangerous.

    One of the pioneers of a completely new approach to road planning and traffic signalization was the recently deceased Dutchman Hans Monderman, who is also introduced by Vanderbilt in his book. The method Mondermann developed for regulating traffic is the complete opposite of the aforementioned “engineering approach”, which designs a road plan around a set of predictable driving mistakes. Monderman, on the other hand, thought of himself as an architect rather than an engineer. For him the problems of traffic regulation involved human factors more than purely physical forces.

    Mondermann’s theory is best summed up by considering two types of spaces in street and road construction. The first is the “traffic space”: this is best represented by the freeway, built exclusively for vehicles and enabling an efficient traffic flow. According to Monderman, the best example of this type of space is the German “autobahn”. Typical environments representing the other basic type of space are city and village centers, which he calls “shared spaces”. Here, the vehicle is only a “guest” or, in the best case, an equal to other participants in traffic, such as pedestrians, cyclists, children, domestic animals, horses and other non-motorized road-users.

    According to Monderman, the crucial mistake committed by classic traffic engineers is to try transferring the rules and standards of the “traffic” space onto the “shared” space. The abundance of traffic signs, road markings and other types of signalization in cities and villages transposes the rules from the world of cars into the world of pedestrians. If the road outside a village is designed in the same way as the road inside the village, only with a speed-limit sign, people will only drive slower if they are afraid of police control. That is why Monderman suggested a radical solution: the shared space in city and village centers should not have any traffic signalization at all.

    The road as a space of participation

    Monderman first tested his ideas in several Dutch villages and towns. In the village of Oudehaske he tried making the main road as “rural” as possible, and after it was rearranged, tested it by measuring speed. He wanted to find out whether the perception of the road really exerts such a strong influence on drivers. When measuring the speed of cars he was at first convinced that his laser speed gun did not work, but he quickly realized what the problem was. Everyone was driving under 30 km/h and the gun could not detect such low speeds.

    In his test village Monderman deliberately did not try to organize the traffic, but intentionally made the conditions it faced more complex by putting pedestrians, cars and cyclists together. Drivers no longer felt comfortable on this road, and as a result had to communicate much more with other people using it.

    Reassured by his initial successes, he decided to take on bigger challenges in cities. In the city of Drachten he rearranged an intersection which made him famous around the world. Although it was an important city intersection through which up to twenty thousand vehicles drove each day, along with a large number of pedestrians and cyclists, he removed all traffic lights and signs, and reduced the road markings to a minimum.

    However, he did not leave the space entirely empty. He added a series of fountains fitted with sensors which could detect traffic density: the water these spray into the air rises higher when the number of vehicles increases at the intersection. He put a round, green plot in the center of the intersection to create a roundabout of sorts, but this was a roundabout which motor vehicles were not allowed to dominate. All the various kinds of traffic meeting at this island must communicate with one another and negotiate their way through co-operatively. Despite the fact that the intersection also includes a driveway to a shopping mall, the traffic is completely fluent, and even more so than it was before, when traffic lights ruled the intersection.

    Videos of traffic at intersections and on roads rearranged by Monderman may be found on YouTube. The thoroughfares reflecting this “psychological” approach to traffic immediately received the name “shared space”. Monderman put so much trust in theories to the extent that he once answered a journalist’s questions right in the middle of a busy road he had planned, and had no problem with walking through his intersection backwards or with his eyes shut. He knew that, because of the way the road and the intersection were organized, drivers would pay equal attention to all kinds of traffic and would not by annoyed by someone “getting in their way”; in Mondermann’s view of traffic flow, we all get in one another’s way, and the only way to proceed is for all concerned to be heedful of one another. Drivers on a Mondermann road would thus even adjust to a weirdo walking backwards across it.