The Capitol Approach Interchange in St. Paul was opened in November 1969, providing a through route for southbound I-35E traffic into the downtown area and to the east and west on I-94. Beginning in the summer of 1968, traffic volumes on I-35E southbound during the morning peak hour were such that congestion and delays occurred between TH 36 and I-94. Breakdowns were almost a daily certainty, with the Maryland Avenue Ramp area the most severely affected.
Several factors were suspected as possible causes, including:
1. inadequate downtown ramp terminal capacity.
2. roadway geometries, generally.
3. restricted width of the Cayuga Bridge, specifically.
4. weaving traffic.
5. combination of several of the factors.
In January of 1969 the Traffic Research Section sought to determine the actual cause of the congestion and to recommend relief measures This activity culminated in the I-35E Ramp Metering Study conducted in July 19&9. This report covers the first in a series of Ramp Metering studies to be conducted in the Twin City Metropolitan Area by the Minnesota Highway Department
The study demonstrated once again that arbitrarily low speed limits, cannot be effectively enforced. Average speeds through the study area stayed essentially the same with or without increased radar enforcement and were not affected by raising the speed limit 5 mph from a value 10 mph below the 85th percentile to a value 5 mph below the 85th percentile.
The present posting of 45 mph speed limits equates with the average speeds. Essentially 50% of the traffic is yet violating the posted speed. Consistent with established principals of speed zoning, the correct speed limit for this area is 50 mph. Accordingly the study recommendation is that the speed limit be raised to 50 mph and additional speed checks be made to measure the effect
if any.
Pedestrian bridges are sometimes constructed as the result of public pressures, i.e. emotional pleas for pedestrian bridges are voiced with safety used as a ploy. But, casual observation has shown that some pedestrians prefer to ignore the safety of bridges that have been provided for them, and cross highways at grade level.
The purpose of this study was to determine pedestrian crossing patterns and degree of pedestrian bridge use in areas where pedestrian bridges exist but pedestrians are not compelled to use them.
