# Cars in the early 1970s

**URL:** <https://boards.straightdope.com/t/cars-in-the-early-1970s/734736>\
**Category:** Factual Questions\
**Created:** [October 15, 2015, 5:27pm UTC](https://boards.straightdope.com/t/cars-in-the-early-1970s/734736 "2015-10-15T17:27:49Z")\
**Posts on this page:** 2\
**Page:** 2

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**Author:** ![SpyOne](https://avatars.discourse-cdn.com/v4/letter/s/82dd89/32.png) [@SpyOne](https://boards.straightdope.com/u/SpyOne)\
**Post date:** [October 17, 2015, 2:09am UTC](https://boards.straightdope.com/t/cars-in-the-early-1970s/734736/21 "2015-10-17T02:09:59Z")

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Our next door neighbors had a car, IIRC a 1970 Pinto, that could sense weight in the(driver’s and/or passenger’s) seats and would sound a buzzer if the seat belt wasn’t buckled. I learned this when I asked why they buckled-in their groceries.

In a Mopar magazine, a guy wrote in to ask about a device he’d found attached to the firewall of a classic car he’d just bought: it wasn’t attached to anything anymore, and it didn’t say what it was on it, and he couldn’t find it in any of the manuals.  
The editors replied that his car was a 1972 model year, and the device was an interlock that would prevent the engine from starting if the driver’s seat belt wasn’t fastened. They said this had been required by a federal regulation that had lasted “roughly until members of Congress started taking delivery of 1972 model-year cars”, and then they repealed the regulation AND made it legal to get the thing disconnected.

My experience with older cars was that warnings were a buzz not a bell, as others have stated above, and I regret I can’t say exactly which years/models had them.

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**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\
**Post date:** [October 17, 2015, 1:39pm UTC](https://boards.straightdope.com/t/cars-in-the-early-1970s/734736/22 "2015-10-17T13:39:18Z")

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The reason cars of the 70s ‘buzzed’ instead of ‘dinging’ was because they used [piezoelectric buzzers.](https://en.wikipedia.org/wiki/Buzzer) Being electro-mechanical devices they had a very limited and harsh sound. By the early 80s these began to be replaced first by less harsh electro-mechanical chime-tone devices then by the late 80s (to today) fully solid state electronics which can be custom designed to make a variety of sounds.

The primary motivation for this was manufacturing costs. Slowly but surely solid state electronics became much, much cheaper to mass produce than electro-mechanical ones. It’s the exact same reason mechanical ignition lock cylinders and uniquely cut metal keys are slowly being replaced with push buttons and.electronic key fobs.

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