Robert:
Thanks for your response. Here's what I'm using for evaluators:
1. MaxHeight attribute
Attribute Name--MaxHeight
Attribute Type--Descriptor
Evaluator Type--Field
Evaluator Logic--[MaxHeight]
The MaxHeight attribute in the streets table is defined as long integer and contains values for vertical clearance in inches i.e. 176 (or 14'6") for segments affected by a clearance issue. For all other segments the value is set to 1000 inches (which effectively allows passsage of any height vehicle).
2.HeightRestriction
Attribute Name--HeightRestriction
Parameter Name--VehicleHeight (default value of 0)
Attribute Type--Restriction
Evaluator Type--Function
Evaluator Logic--MaxHeight < VehicleHeight (I was hoping that I'd mis-entered an = operator as you suggested, but it is <
I have tested some other vehicle heights on the route and the interesting thing is that values in the 0 - 171 inches range pass; values of 172, 173, 174, 175, and 176 fail; and values over 176 pass.