Which is - objectively - the better side of the road to drive on?

February 22, 2018 2:01 PM

For the first time in my life I'm in former british colony countries that drive on the left side of the road. I find some things a lot easier now. And I'm wondering if there's any study or facts that say which side of the road IS better to drive on. Like our eyes reading left to right. Or reaction time for non dominant hands on wheels. Is there any math that says one side is better than the other?
posted by rileyray3000 to Travel & Transportation (7 answers total)

There's nothing inherent about reading left-to-right, as readers of Hebrew, Arabic, or East Asian languages would tell you.

The main difference I see between driving on the left and driving on the right is the location of the gearbox/shifter -- when driving on the left it's by your left (usually non-dominant) hand. I would think that would be harder for most people. Are you yourself left- or right-handed? Or were you "originally" left-handed but forced to switch in school? Many people also have a dominant eye (usually same side as handedness); if you have a strong right-eye dominance, then left-hand drive would be preferable since your "good" eye is closer to oncoming traffic.

I was only able to find one study on this, which is paywalled.
posted by basalganglia at 2:34 PM on February 22, 2018 [4 favorites]

There is no real advantage to driving on either side of the road. Even which hand you shift gears with is irrelevant - it is not a complex hand motion at all, so doesn't require any kind of manual dexterity that your 'non-dominant hand' would have any trouble at all with (assuming no other hand-eye coordination issues).

So, in short, if you were to start a whole new country that had no roads and decided to set a road system up (therefore having the freedom to choose) there is zero argument for picking one side or the other beyond precedent or availability of cars in that configuration (right or left hand drive).
posted by Brockles at 3:50 PM on February 22, 2018

Yep. There's no advantage that I know of (and I study driver behavior) for one or the other, provided you're a skilled driver. The real problems come from switching between the two, because all of your training does not transfer easily when mirror-reversed around the central axis of the vehicle. At a guess, I'd bet the transition is worse for older drivers (any driving-related transition is worse for them), but that's about it.
posted by Making You Bored For Science at 4:11 PM on February 22, 2018 [2 favorites]

Many motorcyclists report that turning right is more difficult than turning left for them when they are first learning. This is probably because the throttle is on the right hand grip. An asymmetry in how the vehicle is controlled causes an asymmetry in driver behavior; it seems reasonable to me that shifting with left vs. right (and thereby steering with the other) certainly could cause asymmetries in car driver behavior as well.
posted by dbx at 8:46 PM on February 22, 2018

What-ho. British driver in Britain here. I'm also a regular visitor to the continent and so familiar with flipping over when required.

The principal difference from my point of view is that on long car journeys I find that whichever arm nearest to the center of the car tends to let go of the wheel and rest on the armrest in the middle - because it's tiring keeping it up without support.

Similarly, in stop-go traffic I tend to leave my hand on the gear stick because of the frequent changes.

In the UK it's my left arm that does this, meaning my right (dominant) hand continues to hold the wheel. I suppose there's a marginal gain here in terms of reaction time and steering sensitivity.


...also when engaging in sword fights on horseback I find left hand drive a more protective orientation.
posted by 5imon at 8:24 AM on February 23, 2018 [4 favorites]

I think there was a slight real advantage to left-hand drive before power steering, where you really wanted to have your dominant hand (typically the right) on the steering wheel, whereas the force required to shift has always been small. These days I think it's a total wash. I've heard that the brain picks up things going from left to right better, so I suppose with right-hand you'd be more likely to see someone turning left from the opposite direction, but that's really stretching it.
posted by wnissen at 10:54 AM on February 23, 2018 [1 favorite]

there is a short conversation at the beginning of the Norwegian movie Kitchen Stories in which Swedish time-and-motion researchers refer to the inherent superiority of left-hand drive (eventually abandoned in Sweden in 1967 on Dagen H).

I have no idea if such studies were done, whether this scene was to indicate the pompousness of Swedes (a common Scandinavian trope), or both. You can see some lovely scenes of left-to-right merging at the Norwegian border in a couple parts of the above-linked trailer, and the elegant solution used instead at the mainland-Hong Kong border, the flipper bridge.
posted by ivan ivanych samovar at 9:30 AM on February 24, 2018 [2 favorites]