We get so much stuff tossed along our small stretch of roadside it seems only fitting that it should be compressed into speed bumps suitable for slowing the tossers enough that they can be identified for punishment by the authorities or, failing that, slowed sufficiently to get a good shot at them.
-- cudgel, May 22 2018

//slowed sufficiently to get a good shot at them.//

Sadly, this is probably counterproductive. A car cruising along at a steady speed is pretty easy to predict. You can dial in the range and lead, pick out a couple of markers etc. Even better, get alongside the road so the car's path is almost parallel to the barrel.

Add in speed bumps, and you create the automotive equivalent of running in zig zags to throw off a sniper. Instead of steady speed, you now have all that speeding up and slowing down that speed bumps compel. This makes a side-on shot difficult. The pitch oscillations caused by the acceleration and braking may also throw off the aim if the target is ahead or behind the vehicle's center of mass.

If the inter-bump zones are a mess of speed and pitch oscillations, then the bump itself might be a natural choice for the shot. After all, the car is slowest here. It's also the most variable. People tend to brake all the way up to a bump and release just as the car meets it, so you move from deceleration to coast with the consequent change in pitch. Then the car meets the bump, the car is forced up and speed is traded for height. How much is hard to estimate, because the suspension takes variable energy from the system. On the down slope the situation reverses.

This is a mess of height, pitch and speed changes. Worse, it's complicated by variables like car length, suspension, load and also how the driver will wobble around in the car. I described the front wheels hitting the bump, but the rear wheels will also, interacting in complex ways.

Or just hose it down with 30mm cannon, if the car's not worth saving.
-- bs0u0155, May 23 2018


^ Have you ever been on grassy knoll in Dallas, you can tell us...
-- not_morrison_rm, May 23 2018


Sorry but my mother-in-law would not make a reliable speed bump.
-- RayfordSteele, May 23 2018


//People tend to brake all the way up to a bump and release just as the car meets it// - just to observe that this is the worst speed bump strategy. Under heavy braking the car 'dives' and the front suspension is compressed and, if the braking is continued right up to the speed bump, the suspension will then be further compressed and may 'bottom out'. A better strategy is to stop braking a moment before hitting the speed bump to give the suspension time to uncompress, ideally hitting the speed bump at the exact moment the suspension has actually bounced beyond its neutral point and is slightly extended.
-- hippo, May 24 2018


The idea is to make speed bumps from anything tossed out of a moving car. We appreciate the technical expertise of your responses on suspension dynamics. We are the recipients of a load of goodies including Bud Light cans and bottles, Polar cups, banana peels(daily), cigarettes& butts, car batteries(yes) and sundry other forms of matter. Compressing this detritus into a revenge type of obstacle tickles our fancy.
-- cudgel, Jun 08 2018



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