APOLOGIES - This got a lot longer than intended, and I wasn't trying to hijack the thread, but there are things most people don't think about that they really should know.
Quote:
Originally Posted by Rock-N-Ruth
We replaced the red lenses with yellow lenses and use them as hazzards.
|
That's an idea, but having two reds up there as high-mount brake lights in addition to high-mount hazards can be the difference between getting rear-ended by something bigger, taller, and heavier than you -- or not. Just my $0.02 as a former semi driver, typical two-filament bulbs for brake / running lights can almost be indiscernible between the two. Sometimes having an extra pair of each that are higher and leave less doubt can make a big difference. An 18-wheeler needs around 600-800 feet to stop at highway speed under optimum conditions.
Which reminds me of something all skoolie owners should understand about their rigs -- especially those with air brakes. I'm sure most of you already understand that these things do not stop or turn like your daily driver. And a tip -- should you encounter an emergency stop on a highway-speed roadway, the sooner you turn those hazards on to warn those behind something is wrong, the sooner they can begin braking. Another reason I recommend a good CB / antenna setup -- Some folks warn of trouble ahead on Channel 19 (not a party line, folks, take chit-chat to another channel). Also allows you to warn others behind you of stopped traffic, etc. Not everyone uses Waze.
But allow me to teach you what semi drivers are taught, and contrary to popular belief, less weight can actually increase stopping distance, because more weight actually improves drive axle traction with a semi. Which puts conventional dog-nose skoolies at a disadvantage off the bat. RE's will be at a disadvantage due to being very light in the front, which typically does 70% of your braking.
Traditional CDL instructional materials state that total braking distance of such vehicles should be around 280-320 feet. However, that is EFFECTIVE BRAKING DISTANCE, not STOPPING distance, which means a world of difference, as you will soon see. Also, these materials are rather outdated, assuming a 55 mph highway speed, which is obsolete for any interstate and many secondary highways. Many highways today have speed limits of 60-70 mph, another consideration to take into account. I have corrected this with my own calculations based on feet traveled per minute at 65 mph.
Also consider that there are three aspects to braking with hydraulic (including air-over-hydraulic) systems, four with air. The figures below are for a fully loaded semi corrected for 65 mph, but consider that a skoolie has a disadvantage to a loaded semi in that more weight on the axles means better traction and less skidding, something I would allow a 10% variance for.
Hydraulic systems are also slightly less effective due to lower pressure in the lines, something I would add another 10% (optimistically I might add) to account for. It sounds crazy, I know, but this is exactly what I was taught in CDL school, and I can tell you I have observed it to be absolutely true in my experience, I don't care what anyone else says. I've had a few near-misses, but my crash and body count is zero after nearly 450,000 miles across the lower 48 in 4 years through all conditions from sunny weather to heavy rain to ice and snow.
1. PERCEPTION DISTANCE - Distance traveled in the time it takes for you to identify a danger. (0.75 sec = 72 ft @ 65 mph)
2. REACTION DISTANCE - Distance traveled in the time it takes for you to apply the brakes. (0.75 sec = 72 ft @ 65 mph)
3. AIR LAG/APPLICATION DISTANCE - Distance traveled in the time it takes for air pressure to reach the brake chambers. (0.5 sec = 48 ft @ 65 mph)
4. STOPPING DISTANCE - Distance traveled with the brakes actually engaged to come to a complete stop. (7 sec = 668 ft @ 65 mph)
Case in point, I was approaching a long curve on I-70 loaded to 79,980 pounds, traveling my usual 63 mph. Suddenly, I saw 2-3 lanes of brake lights just at the end of my visibility (70 feet perception distance). I immediately stood on the brakes (70 feet reaction distance plus 46 feet lag distance). Yes, that truck traveled 186 feet (typical car stopping distance) before the brakes even applied. With good weather, good tires, good brakes, and optimum visibility and traction, given the curve.
Even with the added advantage of an exhaust brake (which nearly no skoolies have) and quick downshifting a manual transmission (also a rarity in this day and age) to help slow the truck, looking at Google Maps, the truck traveled approximately an extra 1/8 mile (660 feet), only to have a near miss and have to bail onto the shoulder at 25-30 mph to avoid another rig, and then continuing to brake as I maneuvered down a cloverleaf exit ramp to get out of the line of fire of anyone else running into that situation with no warning. Getting rear-ended by an 18-wheeler at 30-40 mph is near certain-death probability, no matter what you're driving. 186 + 660 = 846 feet before I scrubbed off 45 mph. So, 900 feet or so at 63 mph, give or take. And lighter vehicles are more likely to lock the brakes up under hard braking. By way of comparison, an 1/8th mile is 660 feet. A 1/4-mile is 1,320 feet.
Therefore...
A skoolie with hydraulic or air-over-hydraulic brakes traveling 65 mph would foreseeably need nearly 850 feet to stop completely from 65 mph, 844 to be exact, but perhaps more due to the slight difference in effectiveness versus air brakes. Adding my disadvantage predictions of 10% for traction and 10% for hydraulic, over 1,000 feet would be needed, 1,013 to be exact -- just about 1/5 of a mile.
A skoolie with air-brakes traveling 65 mph would foreseeably need at least 858 feet to stop completely from 65 mph. Adding my 10% disadvantage prediction of 10% for traction -- I would say call it at least 950 feet just to be safe, also just about 1/5 of a mile.
I'm not telling you folks this to scare you. I just want to educate you to take necessary precaution to avoid any entanglements with the typical wayward idiot on the road today. I can tell you that sitting that high above the highway, I could look down into other vehicles and tell them what they were doing. And eight or nine out of ten were playing with their phone, reading, writing, trimming facial hair, putting on make-up, anything but what they should have been doing. If you can picture it being done in a kitchen, bathroom, dining room, living room, and YES, BEDROOM, I've seen it done at 65 miles per hour (or more) in a vehicle.
One of the worst is the idiots who pay no attention until they're 70 feet from their exit and dive across your nose at 65 mph while braking. I've had a collision mitigation system nearly roll the truck and kill me because of these morons.
And this may offend the ladies out there, but it's the absolute truth -- soccer mom was the biggest offender. Doing 80 on cruise control, steering with her knees because her hands were full with coffee and a bran muffin, phone cupped to her ear with her shoulder, cutting off a 40-ton semi that needs 800 feet to stop, with 20 feet between bumpers going into rush-hour traffic. While I'm growing gray hairs and jamming the brakes, I see four little faces glued to the windows, screaming, "SAVE US! SAVE US! MOMMY (OR DADDY) DRIVES LIKE AN IDIOT!"
Laugh all you want, I've seen it too many times to count. People really are that stupid. At the risk of offending, if brains were gasoline, some folks couldn't run a p*ss-ant's go-kart two laps around a dadgum Cheerio. And too many people are all too happy to trust their safety in a vehicle to a computer that can sometimes get 3 from 1+1. I didn't have any gray hairs before I started driving those trucks, folks, honest.
So, in summary, folks, you can see why I drove 63 mph in those trucks in 65-75 mph zones, and 58 mph in 60-65 mph zones. Educate yourselves and learn from my experience, your travels will be safer and much more enjoyable by accounting for all this...
Because I don't know about you, but if I have to stop suddenly on an interstate because of rubberneckers, I'd love to have a great neon sign flashin' on an' off on the back of my bus, sayin', "Jimmy Buffett, there's a great crash a' comin'"... 'Cause THEY... MIGHT... BE... DRUNK.
Linear Mode
