Drive toward the light
July 4, 2019 2:00 PM Subscribe
Why do people brake while exiting tunnels?
I live in Seattle, there’s plenty of tunnels here, though this mostly affects me on I90 going E onto the bridge. Most people don’t seem to brake while entering a tunnel, but nearly everyone regardless of traffic, weather, visibility, etc slows down significantly while exiting the tunnel. I’ve noticed this in driving other places as well, with a more limited consistency of people braking while exiting a bridge.
Again, this is regardless of traffic or visibility conditions—reliably the person I’m behind slows from regular highway speed to -10 to -15 mph when there is no merging, plenty of light, nobody even in front of them. Light googling turned up no traffic regulatory recognition of this phenomenon.
I honestly only want to know out of curiosity fueled by daily burning irritation. Is this phenomenon a thing?
I live in Seattle, there’s plenty of tunnels here, though this mostly affects me on I90 going E onto the bridge. Most people don’t seem to brake while entering a tunnel, but nearly everyone regardless of traffic, weather, visibility, etc slows down significantly while exiting the tunnel. I’ve noticed this in driving other places as well, with a more limited consistency of people braking while exiting a bridge.
Again, this is regardless of traffic or visibility conditions—reliably the person I’m behind slows from regular highway speed to -10 to -15 mph when there is no merging, plenty of light, nobody even in front of them. Light googling turned up no traffic regulatory recognition of this phenomenon.
I honestly only want to know out of curiosity fueled by daily burning irritation. Is this phenomenon a thing?
For me it is definitely light adjustment. I can't see a thing when I first emerge into the light.
You may consider that the adjustment period is going to vary widely based on what people are born with and how old they are, so from your perspective it may be taking forever.
posted by Tell Me No Lies at 3:06 PM on July 4, 2019 [5 favorites]
You may consider that the adjustment period is going to vary widely based on what people are born with and how old they are, so from your perspective it may be taking forever.
posted by Tell Me No Lies at 3:06 PM on July 4, 2019 [5 favorites]
In addition to what was mentioned, speed limits in tunnels are set pretty low, and usually the police won't and can't pull people over in tunnels. However, the exit of a tunnel is the perfect spot for a speed trap.
posted by Maxwell_Smart at 3:16 PM on July 4, 2019 [10 favorites]
posted by Maxwell_Smart at 3:16 PM on July 4, 2019 [10 favorites]
On top of what everyone else is saying, even if I'm a hypothetical driver with perfect vision, nerves of steel, and zero regard for speed traps, if I'm accustomed to the fact that there's always a fucking slowdown at the end of the fucking tunnel, I'll probably slow down a little in anticipation of it just so I don't have to slam on my brakes at the last minute.
So even people who weren't originally part of the problem end up becoming part of the problem by accommodating people who were already part of the problem.
posted by nebulawindphone at 4:03 PM on July 4, 2019 [2 favorites]
So even people who weren't originally part of the problem end up becoming part of the problem by accommodating people who were already part of the problem.
posted by nebulawindphone at 4:03 PM on July 4, 2019 [2 favorites]
I do it because I do not feel it is wise to propel a ton of metal at great speed into an environment that I have not been able to properly assess because I have just transitioned from dark to light and want my eyeballs to have an opportunity to recalibrate.
posted by turbid dahlia at 5:04 PM on July 4, 2019 [24 favorites]
posted by turbid dahlia at 5:04 PM on July 4, 2019 [24 favorites]
I'd bet a lot of it is simply coping with the change in ambient illumination, particularly if you're going from a tunnel to bright daylight. Your retinas are perfectly happy to cope with both illumination conditions, but at a minimum, your iris takes a fraction of a second to constrict and give you a smaller pupil, so that's probably a big part of it.
posted by Making You Bored For Science at 5:46 PM on July 4, 2019 [2 favorites]
posted by Making You Bored For Science at 5:46 PM on July 4, 2019 [2 favorites]
One psychology professor argues that it comes from an error in the way we visually process speed.
However I must note that contrary to your question, drivers in Pittsburgh definitely slow down as they enter the tunnel as well as when they exit. The joke there is that they are afraid of the tunnel monster.
posted by muddgirl at 5:58 PM on July 4, 2019 [3 favorites]
However I must note that contrary to your question, drivers in Pittsburgh definitely slow down as they enter the tunnel as well as when they exit. The joke there is that they are afraid of the tunnel monster.
posted by muddgirl at 5:58 PM on July 4, 2019 [3 favorites]
Tunnel lighting is a thing. Lighting for some distance prior to the exit is supposed to be of an intensity and colour to ease, if not eliminate, any transition effects. I have not noticed that effect (the slowing at the exits). Of course, maybe some operators are too tight, don't care, etc, and have not installed, or not maintained, such lighting.
posted by GeeEmm at 6:52 PM on July 4, 2019
posted by GeeEmm at 6:52 PM on July 4, 2019
Safety. The reason is safety. Maybe you should think more about safety when piloting a machine that can kill you and many other people in the blink of an eye. We all probably should.
posted by SaltySalticid at 8:38 PM on July 4, 2019 [5 favorites]
posted by SaltySalticid at 8:38 PM on July 4, 2019 [5 favorites]
In addition to the visibility thing I think there's an element of knowing that while you're in the tunnel there isn't going to be stoplight or unexpected slowdown while you're in the tunnel. I actually find myself speeding up unconsciously when I go through tunnels.
Coming out of the tunnel that element is immediately taken away from you and I find myself readying myself in case there is some unexpected stoplight at the end. This may not be rational or logical especially if the tunnel is part of a highway without stoplights but having a lot more visual input and a change of scenery as I exit the tunnel tends to put me in the slowdown and assess what's going on in the road mode.
posted by Karaage at 9:07 PM on July 4, 2019
Coming out of the tunnel that element is immediately taken away from you and I find myself readying myself in case there is some unexpected stoplight at the end. This may not be rational or logical especially if the tunnel is part of a highway without stoplights but having a lot more visual input and a change of scenery as I exit the tunnel tends to put me in the slowdown and assess what's going on in the road mode.
posted by Karaage at 9:07 PM on July 4, 2019
Mobile device use.
posted by sourcequench at 10:16 PM on July 4, 2019
posted by sourcequench at 10:16 PM on July 4, 2019
Mobile device use.
I remember people doing this in the Cassiar Connector when it opened in the early 1990s before much of anyone had mobile devices.
posted by jacquilynne at 10:58 PM on July 4, 2019
I remember people doing this in the Cassiar Connector when it opened in the early 1990s before much of anyone had mobile devices.
posted by jacquilynne at 10:58 PM on July 4, 2019
I slow down when exiting tunnels, and I know it. I do it for two reasons.
First, as everyone else has mentioned, my eyes need time to readjust to the light (unless the tunnel was very short). Second, I'm a cautious driver. I cannot see what's to the left or right of the exit when coming out of a tunnel, so I slow down for the sake of safety. I don't want to hit a cyclist or a pedestrian.
I also slow down when cresting hills, which drives my girlfriend crazy. Or used to. Then once when going over a hill, there were a couple of kids goofing around and straggling into the street. I think she understands now. (But she still gives me a hard time.)
posted by jdroth at 9:06 AM on July 5, 2019
First, as everyone else has mentioned, my eyes need time to readjust to the light (unless the tunnel was very short). Second, I'm a cautious driver. I cannot see what's to the left or right of the exit when coming out of a tunnel, so I slow down for the sake of safety. I don't want to hit a cyclist or a pedestrian.
I also slow down when cresting hills, which drives my girlfriend crazy. Or used to. Then once when going over a hill, there were a couple of kids goofing around and straggling into the street. I think she understands now. (But she still gives me a hard time.)
posted by jdroth at 9:06 AM on July 5, 2019
Mice instinctually do this, they also tend to hug walls and avoid open spaces.
posted by porpoise at 9:27 AM on July 5, 2019
posted by porpoise at 9:27 AM on July 5, 2019
Speculation: tunnels are featureless, have no intersections, and there are few sources of hazard. When you exit, there's a hell of a lot more distraction, maybe intersections, sudden increase in visual stimulus, possible sources of hazard, so you feel less safe and slow a bit. This would be connected to the phenomenon of accidents on long straight featureless highways (people stop paying attention) and European "shared space" street design (where there is little signage and few cues for drivers, forcing them to pay attention, and they slow down).
posted by i_am_joe's_spleen at 1:16 PM on July 5, 2019
posted by i_am_joe's_spleen at 1:16 PM on July 5, 2019
This thread is closed to new comments.
posted by shortyJBot at 2:17 PM on July 4, 2019 [19 favorites]