Watch the on-road fieldtests. And the change from driving on the left to the right side. More than 50 years later, the Scandinavians (let’s not forget Volvo and Finnish specialist Sisu) still outpower all other truck makers. No wonder, with their high gross weight limits, increasing from 110,000 lbs back then to more than 160,000 lbs in our times.
When were the last RHD cars in Sweden sold?. Every body driving on the left in LHD vehicles must have made turning from junctions a little tricky.
Fait produced trucks with RHD well into the 70s as the driver sat near the edge of mountain roads…Safety first…..
Swedish cars had LHD all along. That’s why they could make the transition to driving on the right so easily. And why they did it at all. You’d never get the UK or Japan to switch to driving on the right.
“H-day”, September 3, 1967:
https://en.wikipedia.org/wiki/Dagen_H
Yes those Scania were quite user friendly in their day I’ve driven 140s but nothing oldr. 110.000lbs is the GVM of my current job my truck has a 50 tonne road user license and a Hpmv permit to exceed 44 tonnes normal gross weight for 8 axles it restricts which roads I can drive it on. 60 tonne max is not unusual here but it does make any make of truck work rreall hard pulling up hills my rig has a Cummins isx 15 litre six derated to about 550hp and an awful Eton smart shift 18 speed AMT transmission I drive it in manual mode up and down hills as it has no concept of how and when to shift, Scania have better automatics in that regard but also have hill mode which allows an over Rev feature to make up for the lack of torque, you have to keep the V8 spinning at high rpms where the big American six will pull at low rpm.
A rather interesting video. Not being a commercial truck driver I haven’t really ever thought about the need to establish a baseline horsepower/ torque formula. They didn’t mention the need to improve brake performance or efficiency to match the increased speeds. Did brake systems improve significantly during that time or perhaps lag behind for A while. A quick check shows the Jake-Brake came out in 1961 so that would seem to be great timing. Was the Jake-Brake embraced in Europe or maybe not due to it’s excessive noise when in use?
Some general info here:
https://en.wikipedia.org/wiki/Retarder_(mechanical_engineering)
Well known in Europe is the Voith retarder, introduced in 1963.
Wow, talk about low speed limits. I wasn’t driving in ’64, but I was old enough to be aware of speeds and speed limits. And I remember my Dad driving the family car, a ’56 Ford Convertible with a “T Bird engine” (his description) and a little 2 axle cabover tractor pacing us what seemed all day long on the Pennsylvania Turnpike around ’61 or ’62. We went back and forth I don’t know how many times, he’s pass us, we’d pass him. Which suggests truck speed limits were probably ~65 here at that time. Let alone now where there are some stretches in the once called “mountain states” with 80 MPH speed limits for cars and trucks, though my home state of California limits them to 55.
Interesting to see the methodology that led to the Scania power increases. This triggered a memory of learning about the methodology employed to set US speed limits.
Sherman, set the WayBack machine to 1981.
Fresh out of Army OCS, I had been promoted from Sergeant to 2nd Lieutenant. I also went from being an experienced scout to a green MP. My 1st MP assignment was Redstone Arsenal Alabama. This is not a major post, but it does have a lot of traffic and includes housing areas, industrial areas and multi-lane limited access freeways.
At the time, MPs provided all the traffic enforcement at Redstone with the assistance of a civilian administrative staff. Among that staff was the base traffic engineer. Over the course of my assignment, we became good friends. He taught me a fair bit about the “WHY” of traffic engineering including some history.
I was surprised to learn the extent of the science that goes into everything from sign design and placement to determining what a speed limit should be. That science was codified into the MUTCD (Manual for Uniform Traffic Control Devices) in 1935 and superseded some earlier efforts by groups of states.
In 1981, the MUTCD recommended an 85% rule for setting speed limits. Here’s how we implemented that as MPs
All roads were monitored for things like traffic flow and accidents. On roads with traffic flow problems or excessive accident rates, we’d generally start with a traffic study. This involved counting cars and recording speeds.
Our MPs would be instructed to minimize their presence on the subject section of road for a period of time and avoid pulling over cars on that stretch of road unless the motorist behavior was obviously a danger to others or suggestive of DUI (Driving Under the Influence for any non-US readers). On our post, we’d try to keep this up for at least 2 months. The exact time could vary depending on circumstances and perceived risk. At the end of 2 months, we’d put out unmanned traffic and speed counters.
Those are the black tubes you occasionally drive across. One tube is just a traffic counter. Two tubes count and record speed. Initially some traffic will recognize the tubes and slow down. However, there is no speed law enforcement visible and no real time action is taken on the data. In a short period of time, speeds will return to normal as motorists quickly learn the tubes won’t result in an MP car jumping out from behind a sign somewhere.
Speeds and traffic counts are recorded. When sufficient data is obtained, the counters are removed. How long that is depends on the amount of traffic. The 85% rule suggests a speed limit at which 85% of the traffic travels at or below that speed. Our traffic engineer called this the “natural speed” of a given stretch of road. Not sure if that term is in the MUTCD. Our traffic engineer was fond of Northern Alabama colloquialisms I hadn’t heard before or since.
After the natural speed is determined, the traffic engineer analyzed other data like accident rates and known hazards. For example, Redstone Arsenal’s mission was developing Army missile programs. The Marshall Space Flight Center (once led by Werner von Braun) is located within the Arsenal. The industrial complex of the base even included a few above ground rocket fuel pipelines near a roadway. You’d better believe speeds were adjusted down from the natural speed in such areas and enforcement could seem heavy handed.
After analyzing the natural speed for other risks, our traffic engineer would develop a recommended speed which was usually adopted. I suspect traffic engineers everywhere applies some type of risk analysis to the natural speed, but it would take the subsequent development of the USLIMITS2 system to put a more uniform structure into that risk analysis.
A criticism of the MUTCD 85% rule was that it tended to gradually increase speed limits. While I was an MP, the US had a national 55 mph speed limit, so there was an artificial brake on increasing speeds. Once localities were released from that 55 mpg restriction, safety mavens raised the alarm that the MUTCD 85% rule would start the speed limit increase process anew. This time with cars that were often better isolated and gave less sensation of speed.
In 2008, the FHWA (Federal Highway Administration) developed the USLIMITS2 system. That system coupled the MUTCD 85% rule to a structured risk analysis of other factors. It seemed intended to counter criticism that setting speed limits mainly based on motorist comfort at speed would only encourage people to drive ever faster. By the time USLIMITS2 was introduced, I was long retired from the Army and well into my 2nd career in sales. I had no experience with USLIMITS2 and have nothing useful to offer on that system.
Both the MUTCD and the USLIMITS2 systems are voluntary and have varying degrees of acceptance among the states. Attachment is a map showing status.
I’ll end this with a quote from Redstone Arsenal’s long time traffic engineer. “Sometimes when different groups argue about speed limits, they use my studies like a drunk uses a lamp pole. More for support than illumination.” It was his way of reminding me that regardless of science, US speed limits are eventually a political decision.
Thanks for chiming in, interesting info!