Alberta Transportation’s Bridge Load Evaluation Manual v. 1.1 has more information. The following is from pages 25-26 in the manual:
"The single unit truck (single-unit vehicle) designation (CS1) applies to:
- a single unit truck; and
- a truck tractor and a semi-trailer, in the case where the inter-axle spacing between the truck tractor and the semi-trailer is less than 4.5 metres.
The semi-trailer truck (two-unit vehicle) designation (CS2) applies to:
- a truck and a trailer;
- a truck tractor and semi-trailer, in the case where the inter-axle spacing between the truck tractor and the semi-trailer is 4.5 metres or more;
- a mobile crane with a boom dolly;
- a truck tractor in combination with a single axle semi-trailer and a semi-trailer;
- a truck tractor in combination with a single axle semi-trailer and a pole trailer; and
- a truck or truck tractor in combination with a pole trailer.
The truck train (vehicle train) designation (CS3) applies to:
- a truck tractor in combination with 2 or more trailers;
- a truck and a full trailer with 2 tandem axles, in the case where the inter-axle spacing between the tandem axle groups is 5.0 metres or more;
- a truck tractor in combination with a tandem axle semi-trailer and a semi-trailer; and
- a truck tractor in combination with a tandem axle semi-trailer and a pole trailer."
Last Updated: August 18, 2020