When I mentioned the city of ’s-Hertogenbosch had forgotten to clear one new cycle route of snow in my post two weeks ago, the city quickly responded and the route was gritted right away. For the future the route is now included in the ‘to be cleared main cycle routes’. That was possible because the ‘city’ is of course a number of people working hard. One person read my post and contacted another person who is in charge of planning the actual gritting. A few days later I was contacted, and asked if I’d like to have a look at how ’s-Hertogenbosch works to keep its city streets safe, by clearing the main routes for motorised traffic and those for cyclists of snow and ice. Well, yes of course I was interested!
And so there I was, at the Department of Public Works, to talk to Hans Teeuwen, sanitation specialist, responsible for policies, purchasing and maintenance. Who told me all about this job of getting the streets cleared with an inspirational enthusiasm. I had no idea there was so much to it!
Hans explains there is a policy to keep certain routes clear. Since all streets in Dutch cities are categorised (also because of the ‘sustainable safety’ policy) it is very clear which streets are main routes that must be cleared. In the past, the cycle paths were not really thought important. But there were many complaints about it and the policies shifted slowly towards clearing the cycle paths more as well. Hans: “Especially when the city was elected Cycling City of the Netherlands in 2011, the department of public works felt it was our moral obligation to give the main cycle routes the highest priority. Now the cycle paths are cleared at the same time as the 8 main routes for motorised traffic.” Nobody told the department to do this. But when a city gets an award it wants to show it really earned it and apparently this mechanism triggers decision makers on many levels in that city. Also of highest importance are the streets leading to the police and fire departments, the route to the hospitals, the bus routes and last but not least the routes for trucks carrying dangerous goods. You don’t want them to slip off the road of course. But that was one of the things you wouldn’t immediately think of when you are not an expert.
The city has decided that the main routes must be cleared within three hours. To make that possible there is an array of measures in place.
First of all the weather is constantly monitored. Hans shows me his computer. A weather service created an online real-time service customised for the city of ’s-Hertogenbosch. Hans points at graphs with the current temperatures of the air and the roads, the dew point and wind force. There are two measuring points in the city. Sensors in the road surface that send information of the road surface temperature and even the percentage of salt on the surface. In 2009 a vehicle with infra-red sensors drove all around the city to measure different types of road surface to find the two coldest points in the city. The sensors installed there now function as “pit-canaries”, an early warning system. All this information, combined with weather reports from nearby airports and a specific weather forecast that the city receives every afternoon, makes it possible to precisely decide when to send the vehicles onto the streets. For this decision the city has always someone on duty, 24 hours a day, 7 days a week from October to March. Five people take turns to cover that entire period. The vehicles must be out and about, before the roads get too slippery by either snow or ice and also before rush hour. The city also has contacts with Rijkswaterstaat (the National Road Service, who do the National roads) and the the province (who do the so-called provincial roads). If one of these two sends their vehicles onto the road the others get warned. The city in turn warns the smaller towns in the vicinity, which cannot afford to have such a sophisticated system themselves.
Hans further explains: “Big trucks do the main roads. They usually have a plough (snow blade) in front and they spread salt from the back. The type of salt we use is actually brine; Sodium chloride (NaCl) with water. These vehicles are normally prepared in advance. The same vehicle may be used to water trees in summer but in winter the snow plough (blade) or a brush and the gritting installation are installed onto it. It is most important to get snow and drab off the surface as quickly as possible before it freezes to the road. Then the road surface must be covered with salt and that keeps new snow and ice from getting on to that surface and sticking to it. In the past dry salt was used, but in 2010 the Netherlands was taken by surprise by a very severe winter. That led to salt shortages throughout the winter all over the country. Forced by circumstances everybody got very inventive. From then on gritting was done with a mixture of brine and water. According to the type of ice or snow, the mixture sometimes contains only 22% salt. This wet salt sticks much better to the road, so it can do its job, melting what is left after brushing or shoving the initial snow away, much better. It was thought this would only work for temperatures to -8C but forced by the shortages it is now known snow and ice even melt in temperatures as low as -20C with this method.” Having less salt on the streets also sounds like good news for the environment. Today’s methods are so sophisticated that the roads can be cleared with just 7 grams of wet salt per square metre. In the Netherlands nobody uses sand or gravel to grit the roads because salt washes away but gravel or sand has to be removed in spring.
The cycle paths are cleared with smaller vehicles. They are 2.2 metres wide so they fit on the 2.5 metre wide cycle paths and they can make the tighter turns. The department is very happy with the new kerbs (curbs). The 45 degree angle is not only safer for cyclists but it is also easier to drive over these kerbs with a maintenance vehicle. Especially where the curves are a bit too tight even for these smaller lorries. Having no bollards is also better for both cyclists and maintenance vehicles. Most bollards are taken down all of the winter period (October-March) so you can ask the question why you should have them up again in the rest of the year. Not having them up again would lower the number of accidents of cyclists smashing into the bollards. This is being discussed in many municipalities all around the Netherlands right now.
Only after the level 1 main routes (both for motorised traffic and cycling) are under control (which can take driving that route up to three times) the second level of routes is cleared. These are mainly streets on industrial areas and office parks. Once they are done, the third level of streets gets attention. Pavements in shopping streets, those near homes for the elderly or schools. For these pavements the city has much smaller vehicles. One route for pedestrians belongs to the level 1 main routes: the pavement from central station to the city centre. Level 1 routes are cleared in the middle of the night if necessary. But level 2 and 3 streets are only cleared during normal working hours.
I was impressed when Hans took me to the huge number of (different) gritting vehicles the city has. The three large salt depots combined contain up to 1,500 metric tons of salt and they are obviously huge too. One was entirely empty already, but one was still full. Hans sounds confident when he says: “We have enough salt for the rest of this winter”.
So I had to ask Hans: “What does this all cost?” “The city has a specific budget for clearing the streets in winter. For all the costs, including maintenance to the vehicles (and damage to them), salaries of the drivers, and the actual purchase of salt, but without the purchase of the vehicles, the budget is 250,000 euros per year.” Which, for a municipality with a population of almost 143,000, sounds very efficient.
The video shows how the city of ’s-Hertogenbosch organises the clearing of the municipal streets.
It is not easy to know if people are satisfied with what a city does to keep the streets safe. Seeing if the number of complaints goes down is not the nicest way, but Hans has two examples of just this week that made him very happy. “When someone calls in a national radio show to give the city a compliment on air and when someone in a live TV show says ‘I had a hard time getting to this studio, you guys here in Hilversum should come and have a look how we get things done in ’s-Hertogenbosch’, then I get the feeling we must be doing a good job!”