What Are Water-Filled Bumpers?

Reviewed by

Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on December 22nd, 2023

Reading Time: 4 minutes
Summary
  • Water-filled bumpers were a safety feature on cars back in the 60s. They help reduce damage caused by low-impact collisions, reducing the risk of injuries for drivers and passengers.
  • These bumpers didn’t last long because water freezes during cold weather. They also don’t look great and there are other safety feature alternatives available at the time.
  • Other outdated car features that were once popular include automatic seat belts, ashtrays, and vent windows.

Looking back, many of the innovations in the automobile industry were ingenious and ahead of their time. Car radio in the 30s, air conditioning in the 50s, and electric windows in the 60s are some of the features we still use today.

However, some didn’t stick around because they were ineffective or better versions replaced them. Water-filled bumpers fall in the latter category.

What Are Water-Filled Bumpers?

Water-filled bumpers are soft-cushion bumpers filled with water in industrial-grade tubes or balloons. They were invented by John Rich as a car safety feature back in the 1960s.

Also known as hydraulic bumpers, they had quarter-inch-thick vinyl chloride with water chambers.

Vinyl chloride is used to make polyvinyl chloride, a hard plastic resin in plastic products, such as pipes, wires, cable coatings, and packaging materials. It ensures the bumper won’t burst after minimal contact.

Water-filled bumpers help reduce damage and injuries caused by low-impact collisions. They work best for vehicles traveling at 10 to 20 miles per hour.

Similarly, crash barrels (see photo) filled with water or sand and salt are used on highways. | Image Source: Richard McCuistian

How Do Water-Filled Bumpers Work?

When the hydraulic bumpers hit another vehicle or hard surface, the pressure forces the bumpers to burst, which reduces the impact.

This is a 1967 newspaper photo from the Los Angeles Times showing a demonstration of water-filled bumpers. | Image Source: Richard McCuistian

The bumpers work because of their structure. Water can only escape through restricted openings in their tough vinyl water chambers upon impact. This helps absorb the kinetic energy of the colliding bodies and extends the deceleration period.

If the water in the bumpers bursts after a collision, reusing them is as easy as refilling them. Drivers might also need to refill the bumpers if the water dries out.

Water can freeze in cold weather, so antifreeze is sometimes mixed into the bumper’s fluid.  If the bumpers had frozen water upon impact, they could dish out damage to the vehicle as opposed to absorbing it.

The vinyl structure featured low-temperature flexibility, which helped prevent cracks during impact in extremely cold temperatures.

How Effective Were Water-Filled Bumpers?

According to reports, there was a 69% decrease in accidents thanks to the bumpers. Only 18% of the vehicles that had these bumpers got damaged.

Besides lowering the risk of damages, the bumpers also reduced accident-repair costs, downtime costs, and accident-claim payments.

These were all crucial for the taxi drivers and companies that had the bumpers installed, as it meant more income and reduced expenses for both parties.

Were Water-Filled Bumpers Used?

After testing water-filled bumpers and seeing their success, 100 taxi fleets in New York and San Francisco installed them. Many police departments and other companies also followed suit.

Why Aren’t We Using Water-Filled Bumpers Anymore?

These bumpers didn’t last because their cons outweighed their pros.

The water freezing was a big turn-off for some, as the cost of investing in anti-freeze water as a substitute can add up quickly.

The bumpers also looked unappealing because they’re essentially two black boxes installed on each fender, leaving no room for creativity as far as design goes. In the same vein, the bumpers added to the car’s overall weight, which could hinder handling.

Lastly, while the bumpers have merits, there are simply better alternatives. After all, they don’t work as well for high-speed crashes, which are usually life-threatening.

Other Outdated Car Features That Used to Be Popular

Hydraulic bumpers are not the only car parts that faded from mainstream use. The following features were once popular before automakers developed better versions or people realized they weren’t great long term.

Automatic Seat Belts

Introduced in the late 70s, automatic seat belts were once considered the best solution for traffic death prevention and an excellent substitute for air bags.

They automatically retract along the A-pillar to the B-pillar when people enter the vehicle’s front seat. The passenger must then pull over and buckle the separate lap belt. Otherwise, the automatic, motor-driven belt could cause serious neck and head injuries after a sudden stop or an accident.

Automatic seat belts were retired after two years because they break easily.

Ashtrays

Smoking was cool in the 90s, and many automakers acknowledged this by equipping their units with ashtrays and lighters. The trays are usually on the dashboards, and many non-smokers use them to store coins.

However, because smoking is discouraged nowadays, ashtrays and lighters are no longer standard in vehicles. Most manufacturers replaced them with storage spaces and device charging ports.

Vent Windows

Before air conditioning systems came into the picture, many vehicles ensured ventilation with vent windows. They’re small, triangular glass installations next to the main door windows.

Drivers can open these windows to let the wind into their cabin and stay cool while on the road. The windows angle outward to guide the wind into the vehicle and ensure excellent air circulation. It’s no wonder they were popular in the 60s up to the early 80s.

The rise of air conditioning wasn’t the only reason vent windows were phased out. Fuel efficiency sealed their fate. Experts found that vehicles were more fuel efficient when their A/C was on and their windows were closed than when their cabin air circulation depended solely on a vent window.

About The Authors
Reviewed By Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Written By CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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Published by
CarParts.com Research Team and Richard McCuistian, ASE Certified Master Automobile Technician
Tags: bumper