How to make cycling possible in the snow

We had almost grown unaccustomed to it… snow! The last time there was substantial snow in the south of the Netherlands was in February 2013, almost 2 years ago. But on ‘the 3^rd day of Christmas’ 2014, there was quite a bit of snow to deal with in ’s-Hertogenbosch.

Heavy snow on the Saturday after Christmas in the South of the Netherlands. But this man is not scared off his bicycle!

It was a Saturday, so that meant a lot of people did not have to go to work, myself included. It gave me the opportunity to go out and film. That was very welcome, because I needed some new images of cycling in the snow. Next month I will be one of the speakers on the Winter Cycling Congress in Leeuwarden, where Herbert Tiemens and I will take care together of a breakout session during the congress.

Video: snow in ’s-Hertogenbosch

When I cycled into town on that snowy Saturday morning, the city was not exactly busy. It seemed a lot of people had chosen to stay in their homes and only those who really had to had gone out on the streets. But the city was already working hard to make cycling possible. On such a day the city of ’s-Hertogenbosch usually clears 233 kilometres of its 300 kilometres of separated cycle ways. That is a lot. But it can’t be done all at once of course.

A detail of the map of cleared cycle routes in ’s-Hertogenbosch. (From the Cyclists’ Union Route Planner.) The few red lines that are not highlighted in purple are cycle routes that will not be cleared.

I have shown you before how the gritting is organised. Maybe I shouldn’t use the word ‘gritting’ at all. Because no actual ‘grit’ is spread on the street surfaces in the Netherlands. Gravel or sand would have to be removed again once the snow is gone, but salt washes away. So only salt is spread out on the streets in this country. On the cycle ways the technique is even different. Salt needs to be further dispersed on the surface and wheels of cars do that. But cycle tyres don’t cover a lot of surface, so that would not work on a cycle way. That is why on a cycle way the ‘gritters’ brush the surface first, and then it is sprayed with a mixture of salt and water. That film of salt water does cover the entire surface and that means most of the snow melts instantly on the entire street surface even without tyres to disperse the salt. The difference between routes that were cleared and gritted and those that were not (yet) was huge.

This narrow bridge is one of the routes that will not be cleared of snow and ice. The warning sign informs road users of that fact.

The alternative to that snowy bridge above is right next to it. A traffic light controlled level crossing that is cleared.

We don’t have snow very often in The Netherlands. It differs per region, but on average only 25 days per year the country is covered with a snow deck. Black ice occurs much more often so the municipalities in the Netherlands do have to organise clearing the streets of snow and ice well. In an info-graphic that the city of ’s-Hertogenbosch tweeted, the following facts were mentioned.

The infographic of the city of ’s-Hertogenbosch shows facts about getting the roads and cycle ways cleared of snow and ice. (Further explained in the blog post text.)

There are 18 gritting vehicles; 6 large trucks and two large tractors with trailers, take care of 8 routes for motor traffic. There are 7 smaller trucks and 2 small tractors with trailers, for the 9 cycle routes that are cleared and one small tractor with trailer is used to clear one route for people walking from Central Station to the city centre. The trailers on the cycle ways and the side walk carry the large water tank and an extra motor to drive the rotating brush. The motor of the tractor would not have sufficient power to make that brush function.

To organise the gritting, 20 people are employed in a 24/7 service. To clear one route it takes about 2 hours. On a day with snow or ice, 308 kilometres of lanes for motor vehicles and 233 kilometres of cycle ways are treated with about 36,000 kilograms of salt. The depot has 1.2 million kilograms of salt in stock.

Brushing the cycle way.

The trailer with the salt and the water tank to spray salted water.

Instant success! The sprayed salt water mixture melts away the snow on the full width of the cycle way. Traffic is not needed to spread out the salt further.

Even though the salt use is very efficient (about 7 grams per square metre) all that salt is of course not good for the environment. That is why there are experiments with innovative solutions to clear cycle way surfaces in a different way in the foreseeable future. In Wageningen, a three year experiment is ongoing at the moment, in which part of a cycle way is heated with ground source heat pumps. Because the surface only has to be warmed up to just over freezing point, that can be done very energy efficient. The first real snow during the experiment that now fell, was melted away perfectly.

The heated part of the cycle way in Wageningen is where the snow melts away. The developers reported they will tweak the system in such a way that the striped effect will be gone. (Picture courtesy of Omroep Gelderland)

The recently opened underground cycle parking facility in Beverwijk and the one under construction in Deventer have heated access ramps. So these ramps won’t be slippery in winter conditions without the need for spreading salt.

The wet film of the water/salt mixture keeps the cycle way clear of snow and ice. That is not necessary on the road surface. Without knowledge of these different techniques, an opponent of separated cycling infrastructure drew a wrong conclusion on Twitter: “notice details: street is dry, bike path wet. Guess what will be ice soon…”. No, not that cycle path. On the contrary, the wetness is exactly what protects it against becoming icy.

But it will take some time before those new technical solutions are available on a large scale. And the scale is large. The Dutch Cyclists’ Union have expanded their route-planner with an option that shows all the gritted routes (Option ‘Strooiroutes’) and that is very impressive. All these routes are cleared of snow and ice, to make sure people can continue to cycle on, even in winter conditions.

An incredible number of cycle ways are cleared of snow and ice in the entire country. This detail shows the south of the Netherlands. The city triangle of ’s-Hertogenbosch – Eindhoven and Tilburg. Clearly visible is the fact that also in the country side a lot of routes can be used during winter conditions.