It's high time we allowed people to cycle along motorways. I'm being completely serious because we're spending all of this money on building road space and yet drivers won't stick to these motorways. Therefore it's time to allow cycling along them.
Now I've got your attention and created outrage amongst the people who don't bother to read the detail, I'll explain myself. In the UK it is against the law to cycle on a motorway (known as special roads in law) as well as there being a ban on walking, horse riding, riding small mopeds and learner drivers and so on; but there are motorways where people are allowed to cycle, even though it's only over short sections.
The Severn Bridge which carries the M48 over River Severn between Bristol and Chepstow allows walking and cycling because it was built wide enough to provide a shared-use cycle track on each side;
The Severn Bridge carries NCN4 across the Severn where it links up with local roads in the communities of Aust and Bulwark. These communities are just under 5km apart which makes it a very easy distance to cycle.
The Grade I listed bridge was built in 1966 and features cantilevered sections on each side of the main structure which carries the shared-use path as can be seen below in this image from the University of Bristol;
As you can see, the cantilevered sections are attached to the main box structure forming the traffic deck and as such, are not part of the load carrying arrangements for the bridge; although the cantilevers in themselves do of course add weight to be carried.
When you think about it, the development of the bridge with shared-use cycle tracks made perfect sense in terms of the distance between settlements and the opportunity for people to cycle. The newer crossing on the diverted M4 to the south (the M4 used to cross the Severn Bridge) is a bit longer between settlements, but no opportunity has been provided for people cycling (or walking, despite the distance).
I've had a dig around and a think and I am not sure there is another motorway which carries a cycle track, but please let me know if you know better because this is an interesting subject. The Forth Road Bridge used to be the A90 and allowed cycling, but since the adjacent Queensferry Crossing was built, it's been reclassified as the A9000 with the new bridge becoming the M90. So near, yet so far! However, it was another product of the 1960s where the UK led the world in bridge design and construction, opening in 1964.
If we go with the Forth Road Bridge and widen this trawl out to trunk roads, then we've the Tamar Road Bridge between Plymouth and Cornwall which opened in 1961 and widened/ strengthened in 1999 with cantilevered decks. It has a walking and cycling link on it's southern cantilever.
Then we've the Humber Bridge between Barton-on-Humber and Hessle which opened in 1981 and which has a shared-use cycle track on each side;
Once we get into 1991 when the QEII bridge at Dartford was built, we have given up adding cycle tracks to major road bridges. The Dartford Tunnel originally had a bus taking people across (including cycles), but now you have to present yourself at the crossing point and wait to be taken across by the crossing control team - it can can 15 minutes until they arrive, it's not a 24-hour a day service and if you are in a group of more than 3 or using a non-standard cycle, you need to speak to the operator in advance.
Of course, there are lots of trunk roads with shared-use cycle tracks next to them, but also many without and it's got me thinking about our policies around major infrastructure schemes. For Highways England schemes, there is a process for Walking, Cycling and Horse Riding Assessment & Review (WCHAR) which should pick up opportunities, although from what I know about the process, the adoption of opportunities is sporadic.
I'm actually thinking around something a bit more specific in that all new infrastructure schemes should have specific requirements to go and find opportunities - maybe anything requiring a Development Consent Order or similar (because of devolved powers) or another trigger point - reviews should also ensure that large projects don't in themselves create new barriers to future walking/ cycling/ horse riding provision.
We should also have a proactive review of existing assets to look for connection opportunities. For example the M25 at Waltham Cross crosses the River Lea and the A121 - could adding a cycle track to the existing motorway bridge provide some east-west connections to NCN1 which runs north-south here (used as an example because I've ridden under it)?
The image above shows the position of a cycle bridge to the south of the M25 with linking paths in purple. Even if the existing structure cannot be added to, there's certainly a pretty clear route for a parallel structure.
Of course, it comes as no surprise that in the Netherlands, adding cycle tracks to major bridge schemes is routine (and it applies to road and rail). In the grand scheme of things, like our great river crossings that I started this post with, this approach is everywhere across the North Sea;
Of course, it doesn't have to be bridges. Any major scheme which creates a connection advantage should be properly explored because with land acquisition and build costs, the extra needed really doesn't dent the budget, especially as haul roads and construction compounds are the norm - space which could be repurposed for connection and maintenance advantages. Mind you with the scrapped cycle route along side HS2, I won't hold my breath.
The M2 has a parallel walking and cycling link over the Medway, thanks to Rob Fairhead for spotting.
The M5 has a parallel walking and cycling link over the Avon, thanks to Toby Wells for spotting.