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John Ducker: Four-way flashers a great modern safety feature

Big construction zones among proper uses for flashers
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Four-way flashers alert drivers to possible emergency situations. Nissan, TNS

We just returned from a 10,000-kilometre driving round trip to Ontario last week. A journey of that length certainly gave me lots to write about. Coincidentally I received an email recently from Susan asking about the proper use of four-way flashing lights on your vehicle. That’s topical for me because on a journey of that length I saw lots of four-way flashers being used — most properly — but other times not so much.

Susan wrote that when she leaves home on her side street she often turns onto a much busier road which is on a hill with curves and which approaches a crosswalk nearby. Often she will activate her four way flashers to warn drivers approaching from behind that traffic is stopping and/or the crosswalk is in use.

B.C.’s motor vehicle act has something to say about four-way flashers but unfortunately it’s ambiguous. Buried deep inside the nerdy part of the motor vehicle act are lamp regulations, or lights as we now actually call them in 2024. A lamp is something Florence Nightingale carried around the hospital wards of 1850s Crimea.

That regulation in question says that turn signals may be used as warning lights by certain types of slow-moving vehicles or whenever a vehicle is disabled on a highway. A slow-moving vehicle is one that is basically carrying machinery or equipment and which normally travels on the road at 40 km/h or less. The classic example of this of course is farm equipment.

If you’re a regular user of the Coquihalla highway you’ll see lots of four-way flashers. Heavy commercial trucks use them to warn other motorists that their speed has been greatly reduced, which is often the case on those steep mountain grades. That one is a definite courtesy to other drivers, conforms to the law and is a no-brainer. Those rigs are truly crawling along compared to the 120 km/h limit permitted on most of that highway.

The other time I see four-way flashers being appropriately used is in big construction zones, and there are plenty of those in eastern B.C., when work vehicles or other equipment have to enter the highway briefly in order to set themselves up for the next job.

There are however several concerns if you overuse your four-way flashers. The basic rule for me is that four-way flashers are used when your vehicle itself is creating a possible hazard. The obvious examples would be a flat tire, mechanical break down or medical emergency. Many jurisdictions throughout North America prohibit their use in any other situation.

In rural North Dakota along interstate 94 there was road construction that appeared suddenly on the horizon. Normally U.S. interstates provide lots of forewarning but not this time. Traffic had to slow quickly. That’s a big deal when the speed limit is 120 km/h (75 mph) and one pickup truck, about half a kilometre ahead, flipped on his four ways as he came to the back of the line.

I get the intention but I don’t feel that’s the best idea, the reason being that those signals could be seen as someone who has stopped dead. That could lead to sudden lane changes, which on a freeway is the last thing to do as traffic is compacting to a sudden stop.

When I come to incidents where traffic is slowing fast in front of me I tap the brake 3 or 4 times to tell drivers behind there is something abnormal happening. That’s an alert — with no confusion that I might have broken down.

There’s debate about using four- ways in bad weather. Anyone with a few years of driving experience has encountered rain, snow or fog that is so bad you can barely see the road in front of you. The safest strategy is to move right off the road. But often that’s not possible. So using four-ways to move if you’re crawling might be OK during extremes. But several road safety officials and cops advise against it. The benchmark then is that you’re dead slow and can barely see.

It’s also OK to switch on four-ways if you’re being pulled over by the cops. It lets them know you’ve seen them and are stopping. But I prefer to simply use a simple left or right hand signal when I pull over for an emergency vehicle which is passing me.

Finally, when four-way flashers are on in many vehicles today your turn signals are deactivated. This could, and has, confused other drivers who also might not be able to distinguish four-ways from your brake lights.

Bottom line: Four-ways are a great modern safety feature. Use them wisely.

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