If I had £1 for every time anyone in the UK said “They should widen this road to help with congestion”, or “Cycle lanes cause congestion”, I’d be a very rich man! However, it’s easy to see why so many people make those same basic mistakes. At least on the surface, it seems to make sense that congestion is simply the result of not enough road space, right? And we all know that cycle lanes take road space away from cars. But let’s dive deeper.
Roads
Let’s start with the UK’s road network. In the UK, there’s an extensive, well-developed road network, offering around 262 300 miles of roads. That only tells us part of the picture though. Some of those roads are very narrow, rural lanes, while some are multi-lane motorways. Regardless, for a physically quite small country, that’s a lot of road.
Motorway started being built in the early 70s, and by 1972, the first 1000 miles of motorways in the UK were built. Motorways are the safest roads, due to limitations, restrictions, and design elements. For example, pedestrians, cyclists, horse riders, and motorcycles with engine capacity below 50cc aren’t permitted to use them. Additionally, they’re normally well fenced-in, and while it does occasionally happen, you’re very unlikely to encounter livestock on motorways.
Rural roads are, statistically speaking, the most dangerous roads in the UK. In addition to pedestrians, cyclists, horse riders, tractors, normal cars, vans and even HGVs using them, rural roads are often a single narrow lane.
Cars
Overall, between 1980 and 2005, road traffic increased by 80%, but during the same period, road capacity only increased by 10%. That doesn’t paint a clear enough picture though, and it’s important to understand that we have more cars than ever before on the roads, and cars are driven more than ever before.
In 1980, there were little over 15 million cars in the UK. By 1990, there were 22 million cars, and that further increased to 26 million, by the year 2000. That growth remains unstoppable: by 2010, there were over 30 million cars in the UK. By the end of 2024, there were 42 million cars in the UK.
Not only are there more cars, but cars themselves are getting bigger all the time. This visual tool demonstrates that quite clearly. Oh, and woe betide anyone who asks people to justify why they feel the need to drive such huge monstrosities. Crucially, cars became much wider over the years, requiring ever more road width. Suddenly, roads that used to be comfortably wide enough for a row of parked cars, and two lanes of traffic in either direction are now essentially single lane roads, with cars parked on both sides, and extremely little space to drive in.
Cars also became heavier, and heavier cars take longer to stop. This is an important point, as it directly impacts on what’s know as the dynamic envelope a car needs. When driving, you need physical space for your car (obviously) plus a safe following distance between your car, and the car in front. All that space combine is the dynamic envelope, and it increases with speed.
Road danger
The primary cause of road danger comes from drivers driving their cars. During 2023, drivers killed an average of 4.49 people per day on the UK’s roads, and seriously injured 77 people per day. That’s the equivalent of two full Airbus A380 planes crashing each year, with the loss of everyone on board. If that happened, ALL those planes would be grounded, until they could be made safe again. Yet when people are killed by drivers, we shrug our shoulders.
The roads are dangerous, and it’s getting worse: according to the RAC, 58% of drivers admit to regularly speeding. When we combine that with the heavier, bigger cars, the road danger increases exponentially.
Yet when you visit any UK news media site (especially that of the BBC, or the cesspits that are the Daily Mail, Express, or any Reach PLC sites) you won’t see ANY of this information. Instead, you’ll see artificial culture wars being stoked about how escooters are supposedly lethal to other road users. You’ll see attack after attack on cyclists, and you’ll see ludicrous claims about how cycle lanes supposedly cause congestion.
Also, while SUVs can be safer for the occupants, they’re lethal to anyone outside the vehicle. Especially children are at severe risk of death when hit by oversized SUVs.
Congestion
Here’s a simple mental exercise: assuming the average car was 3.5 metres x 2 metres, see if you can calculate how many such cars you can park on a rugby pitch (100 metres x 50 metres). The answer should be 714 cars, assuming they’re physically touching.
Now do the same exercise, only this time, each car is 4.5 metres x 2.8 metres – how many cars can you fit in now? You should find the answer dropped to 396 – little over half as many as before! And that makes sense, doesn’t? You can get more smaller things into the same space as you can do with larger objects. That’s not exactly rocket science!
As we’ve clearly seen, our existing road space is limited, but there greater demands being made of it. That means we need to start look at efficiencies. We know that an average traffic lane of 3.5 metres wide is at full capacity when 2 000 cars per hour drive through. Now, if each of those cars was carrying 4 people, we’d be looking at 8 000 people per hour. We also know that the vast majority of cars have just a single occupant.
If we took that same lane, and made it a cycle lane, we can move between 8 000 to 14 000 people per hour (depending on how close people are happy to cycle to each other). That’s a vast improvement in efficiency. In addition, if 8 000 people chose to cycle, instead of drive, that’s 8 000 fewer cars that require parking.
It is painfully obvious why roads are congested: we have too many drivers, driving too many cars. At this point, people usually start with the “Just add more lanes” arguments.
In 1955, Lewis Mumford said “Building more roads to prevent congestion is like a fat man loosening his belt to prevent obesity“. That statement is as true today as it was then. In fact, contrary to expectations, we know road widening causes something called induced demand. The government defines induced demand as ‘the increment in new vehicle traffic that would not have occurred without the improvement of the network capacity’.
In simple terms, the more roads we build, the more people drive. As an excellent example, within 3 years of widening, London’s M25 motorway was just as congested as before widening. When someone tells you “Just add another lane”, what they’re actually telling you is they don’t have the beginnings of an understanding of traffic management.
There’s an opposite to induced demand, and that’s called traffic evaporation, and is defined as the reduction in traffic flows which is often observed following a reduction in road space capacity. In short, when you reduce road space for cars, fewer people choose to drive, and there are fewer cars on the road.
Conclusion
In an on-demand, instant, now world, people are increasingly reluctant to delve deeper, to form a better understanding. After all, it’s quicker and easier to simply grasp at tired old tropes, like “cycle lanes cause congestion”.
ALL the evidence is clear and conclusive: cycle lanes do not cause congestion. Too many cars cause congestion. If after reading this entire article, you still harp on about adding more road space, and complaining that cycle lanes supposedly cause congestion, I have some bad news for you: You will have confirmed that you’re a blithering idiot.
Another well-researched and well-written post. We need a change in mindset in this country from those in charge. Unfortunately, that would mean more people with integrity. Which is in short supply.