Wednesday, 27 January 2016

Passenger Car Units

When I've been saying vehicles per day or per hour, I actually meant passenger car units per hour or per day or whatever time period. I just used vehicles per hour because it is easy to understand. It's how many vehicles arrive over 24 hours or over 1 hour or whatever. But the reality of traffic is different.

In the realm of traffic engineering, they actually use Passenger Car Units, or PCU. This accounts for how much of an impact various types of vehicles have on the flow of traffic and capacity. Large vehicles effectively count for more than one car, a many bicycles can use the same space taken by a single car, and similar relationships.

I will use the following chart to describe how PCUs will work to me, and how they would be used whenever I say vp(time representation letter, like hour, day, etc) but mean PCU.

A car is 1. This also counts light trucks and vans, up to 3500 kg and no more than about 6 metres in length. Ordinary vehicle to most.

A single unit truck (meaning that the cab and the cargo part is fixed together, or at least they don't have an articulation) is 1.5 PCU. And this will count trucks and vans over 3500 kilograms.

Multi unit truck, basically meaning any truck with an articulation is 3.

Ordinary buses, 12 metres long, the ubiquitous city buses, and also the non articulated coach buses, are 2.5.

Articulated buses ate also 3.

Motorcycles (engine size over 49 cubic centimetres, no limiter and needing a class 6 license (in Alberta) to ride), will be .5.

Mopeds and bicycles will be .2. Mopeds being 2 or 3 wheeled motorized vehicles that are not motorcycles. Bicycles including E bikes.

So remember that PCU/d is what I mean if I say vpd or vpd or similar. I just use the latter because it's easier to understand and explain. There are of course times when we want to talk about specific vehicles, but in terms of capacity and modeling, this is how I am rolling. Pun intended.

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