Roadways! They’re supposed to be clear paved routes for vehicles to safely pass through. In Calgary, Canada, however, the local road authorities occasionally diverted from this idea. They built giant pits to trap vehicles that dared to venture the wrong path.
There are all kinds of access control measures you can use to block a roadway. There are tire spikes, bollards, and boom gates if you desire to have selective access for some vehicles and not others. But seldom do we see authorities building actual traps to ensnare vehicles, while damaging them in the process.
The City of Calgary believed it had a good reason to do this. The intention was to create “transit-only” areas where public buses could travel, but personal vehicles could not. Thus was spawned a trap to capture the cars of unwary drivers going the wrong way.
Gotcha
The traffic control devices were commonly referred to as “bus traps.” It was a somewhat confusing name, as city buses were perfectly capable of passing over the traps unscathed. Instead, they were intended to stop commuter cars from entering designated transit-only lanes.
The design was quite simple. The traps consisted of a pit dug into the roadway, roughly a foot deep or so. The trap was reinforced with iron plating around the edges. Multiple large rollers span the trap which add a further obstacle to any vehicles that might happen to fall into it. They make it far more likely a vehicle will get stuck and be unable to reverse out of the trap. The traps worked by a very simple method—city buses were wide enough to drive over them without falling in. Regular commuter vehicles were narrower, and would get stuck.
After their installation in the 1970s, the bus traps soon became notorious in Calgary, trapping unaware drivers on the regular. All despite massive signs on each one, reading “DANGER: DO NOT ENTER. ROAD IMPASSABLE. VEHICLE TRAP IMBEDDED IN ROADWAY.” Of course, nobody is quite as good at missing an obvious road sign as a driver who has already decided where they’re going.
The traps had their drawbacks. They were intended to prevent regular traffic from using transit-only lanes. But, in the event somebody tried to drive through anyway, they’d end up blocking the very lane that the trap was supposed to keep clear.
The bus traps proved controversial, and not only because of their ability to trash cars that got stuck in them. The traps were often installed within neighborhoods on sections of road that were incredibly tedious to detour around. Oftentimes, a driver’s desire to take the shortcut got the better of them, before shortly bringing their vehicle to grief.
By 2024, the city had changed its position, noting the traps were not an ideal solution. “Ending up in a bus trap resulted in damages and costs as well as being a scary experience for drivers,” read the city’s statement. “They’re also counterproductive because transit service is interrupted when a vehicle is stuck in the exact lane that was meant to be kept clear.” Beyond these obvious problems, the traps had other drawbacks, too. They prevented the city’s smaller shuttle buses and emergency vehicles from using transit-only lanes, as well.
I swear I see this at least once a week. #yyc @CalgaryPolice @calgarytransit Bus trap at Centre and Beddington Trail pic.twitter.com/5aiPgaYCEq
— Tremaine (@tremaine) July 5, 2019
Another chapter of the bus trap series. pic.twitter.com/a5COgW5Lkk
— ???????? That AC Fan at CYYC (@JesseLiOH) October 30, 2023
It was eventually decided that the traps would be removed. The last seven were filled in during the early months of 2024. The city was still adamant that drivers were not to use transit-only lanes as shortcuts or for regular travel, but the punitive traps would no longer be in place. Instead, the city switched to simple signage to indicate the status of transit-only roads, with traffic cameras a potential addition if more enforcement was required.
Calgary isn’t the only city to have explored the use of bus traps. The city of Hillerød in Denmark used similar constructions for much the same reason. Meanwhile, those boisterous Australians have a creative version all their own—with sump-smashing devices installed on the Adelaide O-Bahn.
Canada’s bus traps are now gone, a memory of an era when traffic enforcement was punitive and brutal. These days, cities like to avoid bent metal and broken glass, preferring to snap photos and send fines instead.
Image credits: City of Calgary, DanOCan via YouTube Screenshot
I’m pretty confident that would just be a fun challenge in my Land Rover.
The current UK system is to put up some signs, and then a camera that automatically fines any non-buses that drive though.
They’ve literally made hundreds of thousands in just a few weeks, because as these bus traps prove, there is no amount of signs that will be enough for all drivers:
https://www.bbc.co.uk/news/articles/c7203gxpe8vo
That one woman blaming it on her sat-nav! If it told her to drive off a cliff, she probably would.
You can see a similar device in this little video I made about 15 years ago. It protects a parking facility reserved for buses in Antwerp, Belgium. https://www.youtube.com/watch?v=zu8uXQu8MyE
If they’re relying on the bus’ width in order to implement a traffic deterrent, then wouldn’t it be a good idea to have a switch system that conforms to the dimensions of the bus? Two soft levers, one high, one low, the high one on the left, the low one on the right. The bus should be heavy, wide, tall, and sturdy enough to push the levers and lower some sort of barrier. All mechanical. The barrier should be slightly before the levers to take advantage of the flat face and overhang of a transit bus, so something like a brodozer can’t trigger the system because the front of the truck will have hit the barrier before the cab can push the levers (if the high ride height doesn’t invalidate the lower one). So long as the levers are rotated the barrier stays down, and they have a dampening spring or perhaps a pneumatic rod that makes sure they don’t just snap back into place and cause the barrier to hit the bus from underneath if it has a bike rack on the back.
Or, y’know. Big hole. Big hole works.
One medieval device I read about relied on the trolleys narrower track to destroy wider vehicles.
Especially effective at discouraging tourism that never expected it.
One reason why the brick road became such a thing was that on packed dirt or flagstone roads horse carts were gouging them out or displacing the stones. Horses and the carriages or buggies they pulled caused such damage to roads that some places banned them entirely. Other places would intentionally place stairs on what were previously surface streets so that the horse carts couldn’t climb them. Germany really liked doing the stairs thing to prevent carriages within the town centers. What’s even funnier is that spiral staircases in fortifications were put in place because military horses only had riders, and the riders would charge up the stairs to break shield blockades.
This has been a problem in one form or another for a long time.
I have never thought of a horse charging up stairs before.
The earliest security tactic was a right angle turn entering a doorway, sometimes complicated by stairs, or ladders.
This is still effective for slowing down intruders.
I’ve always heard spiral stairs were designed to enable defenders coming down while restricting the sword arm of attackers.
Those stairs often had every change possible to handicap intruders going uphill.
Even milder ones keep you off balance as every step changes from the last.
Tourists often assume this was sloppy work, but really very thought out.
At best, stair design is more complex than it looks.
If you ever have to build even short stairs, get a book on the engineering.
My first set was great going up, but dangerous going down.
Re, brick roads, I thought stone was tougher?
Aren’t some Roman stone roads still functional?
The cobble and sometimes flagstone Roman roads got pretty torn up by around the 600s once the quarries got abandoned, and a good chunk of them had been returned to dirt by the 900s* in northern Europe. The old Roman roads worked great for a Mediterranean climate, not so much a Temperate or Sub-Arctic one that goes through freeze-thaw cycles (a familiar modern problem). Most of what survived were the ones in Greece, Italy, and the Levant. The ones in the British Isles are oddities, because just like the pools at Bath, without constant wars with massive armies they were in good enough shape that they were just left to decay rather than be modified or replaced.
So what happens when you don’t have the ability to easily replace the cobblestone pavers? Take them out, use them to build other stuff, and replace them with bricks. Bricks are uniform, easy to manufacture if you’ve got access to mud or clay, easy to replace, are such a simple concept a child could pave a road, and are somewhat easier to sweep animal shit off of. Thus starting in the 1300s when horse and mule drawn vehicles became more common you had a large number of places start using bricks for their roads. By around the 1500s that was replaced with cobblestone (or returned to) as Europe was quarrying en-masse again due to the Renaissance, and then bricks became a thing again in the late 1880s as the Progressive Age started and then the Garden Cities movement came into vogue and made city sanitation a focus.
* Related, this was not long before the mass adoption of the horse by former Roman held territories. Before about 600BCE most breeds of horses were often too small or not stout enough to ride or use as beasts of burden and were used as drag animals (pulling chariots and sleds, as plows were by oxen and carts by donkey), and the ones that could be were bred and kept as military assets. It wasn’t until about the 500s CE that the larger breeds of horses became common enough to replace smaller donkeys as full draught animals. The spread of feudalism severely slowed down their adoption however since serfs weren’t allowed to leave the fief they were born on and the nobility only saw horses as esteemed military assets, but the Great Famine and Bubonic Plague back to back caused such a labour shortage that horses were quickly adopted after the 1350s.
In case I wasn’t specific enough about how bad sabotaged staircases can be, I hope you get the chance to try one.
Even a shorter step can trip you up.
The only thing not being altered on defensive staircases was the width.
Angle left or right would shift, each steps height would be different, depth could be shorter or longer.
You could easily end up on all fours.
Traffic engineer here. The earliest bus signaling equipment was just a beam something like 9′ high that buses would hit to trigger a gate. We’ve long had encoded light signaling for things like bus priority (and fire preemption).
Why levers? Today you just use a transponder. Example – the bus entry to the DFW airport Rental Car Center. The buses just drive up to the gate, and the gate automagically opens for them. The car pit seems a bit dumb in that it’s blocked until the tow truck gets there. The British camera system seems smarter than that, and far more profitable, but then you still have cars GOING where they are not supposed to be.
I was thinking of what they’d have had in the 1980s when this was built.
In Europe they have retractable bollards in bus lanes, that occasionally impale tailgating cars.
I may be nuts but how about a garage door sans garage where as a transit bus the door opens but a civilian vehicle driven by a taxpayer who paid for the transit lane cannot open?
Toronto has had issues with cars going into one of its street car tunnels.
Gates work, until someone follows a street car into the tunnel:
https://www.blogto.com/city/2023/12/car-stuck-ttc-queens-quay-streetcar-tunnel/
Another Calgarian here. I used to live in a neighborhood that had one of these and it would catch someone at least once/month. When it happened, the buses would have a 10-15m trip to get back to their route, so it caused chaos.
One day, I was standing at the bus stop and a woman drove up to the trap. She was obviously considering it, so everyone at the bus stop started yelling “No!”. She went for it and crashed into the trap. We rushed over and she tearfully said “I thought you said go.”
On the plus side, it was a great shortcut on a motorcycle!
How much trouble would it be to put a movable arm barrier? Or do the bus drivers not like slowing down?
Exposed mechanical barrier in a harsh climate does not portend reliability.
So how does you explain all the exposed mechanical barriers used in northern states to close interstates, block rail crossings, keep me from using a permit only parking lot? Yeah, no….they work fine. Calgary big brained this one.
Easy and cheap and zero maintenance. These were put in when Calgary was generously 500K people. You don’t have to run power or maintain them or worry about vandalism. It’s a hole in the ground. Don’t want to get stuck, don’t drive into it.
How do they get out before the next bus?
Whomp Whomp – they don’t.
They don’t
Built in America, though I think Canada has the same if not better ability. Ratatejas might be southern us or even Mexican
I’m Canadian/US dual. Born and raised in Canada, living in the States since 2008.
So my brain went to another engineered solution, a bollard that is pushed down by the bus’ track and weight. Purely mechanical.
Calgary native here. The signage was infinite. You needed to be a special level of blind to not realize what was going on. Of course some drivers don’t actually believe that the city would willingly f your shit up, but they were in place since the ’80s.
Part of the placement is to calm traffic. Calgary has a fairly extensive bus system through almost every neighborhood in the city, and in winter, bus routes are the first streets to be plowed. Residential surface streets don’t get plowed at all. A lot of the bus routes have what works out to be shortcuts through neighborhoods and back onto main roads. The city doesn’t want these residential streets to become primary routes.
The one marked “Beddington” in one of the above pictures has been there since the mid-80’s, and I lived close by when it was put in. The neighborhood was once the edge of the city, and people used the residential street as the fastest way out of town as it connected with a secondary highway, but as the city grew you had a residential street, complete with street parking become a main thoroughfare, hence the bus trap. Allows Transit to complete their route, but takes out a short-cut.
As to crossing them now, your average bro-dozer/penis compensator may be able to straddle them, but they weren’t really a thing 40-50 years ago when these went in.
Edmonton had these and another type that had a tall concrete wedge as well that would stop you- they took them out due to liability as I understand
These were clearly intended to result in legal bills.