85 percent of the northbound trucks), seven- to nine-axle Rocky Mountain doubles (roughly 10 percent of both the northbound and southbound trucks), and (primarily) eight-axle Canadian B- trains (6 percent of the northbound trucks and 16 percent of the southbound trucks).
Section 1023 of ISTEA and an associated Memorandum of Understanding between Alberta and Montana allow trucks to run on I-15 between the border and Shelby at Canadian RTAC axle weights and GVWs. Section 1023 also excludes these trucks from compliance with Bridge Formula B. The commodities which have most benefitted from this ISTEA provision are truckloads of fuel oil, sand, grains, potash, fertilizer, and agricultural products.
The BN exchanges with Canadian Pacific Railway and trucks at this crossing. Grain and other commodities are increasingly being trucked from southern Alberta into Montana for transshipment with Burlington Northern.
4.2.5 Portal-North Portal
This is the fifth highest volume crossing on the western border, averaging 301 trucks per day in 1994 (two-way), which is 26 percent higher than in 1992. Southbound traffic is dominated by truckload movements of wood, paper, printed material, chemicals, livestock, and other agricultural products. Seventy-five percent of the northbound movements through this crossing are conducted by Canadian-registered vehicles.
Truck characteristics at this crossing are primarily controlled by U.S. regulations, and in particular those emanating from North Dakota and States south, and the U.S. Federal law. Not being an IS route, there is no ISTEA GVW freeze applied to U.S. Route 52. Because U.S. Route 52 is an NN highway, it is subject to an ISTEA length freeze of 103-foot cargo-carrying unit length for double cargo unit combinations.
There are many unique truck configurations operating on the crossing. These result from the combined effects of the governing TS&W regulations, commodity handlings and intermodal operations present in the region. Examples include five- to seven-axle truck-trailers, six- to seven-axle tractor-semitrailers, seven- to nine-axle Rocky Mountain doubles, and (primarily) eight-axle Canadian B-trains. Due to the spring thaw, weight restrictions in North Dakota, southern Saskatchewan, and southern Manitoba lead to re-routing of heavy truck traffic through this region and across the border during the spring.
This is the second highest volume crossing on the western border, averaging 669 trucks per day in 1994 (two-way), which is 61 percent higher than in 1992. Deducting the effect of the virtual closure of the Noyes-Emerson crossing since 1992 on re-routing traffic to the Pembina-Emerson crossing, the real growth rate of the Pembina-Emerson crossing since 1992 is about 20 percent. Southbound traffic includes movements of lumber, peat moss (to Texas and Arizona), paper rolls,