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OCR for page 12
12 FIGURE 3 An example of graphics that Mn/DOT provides to customers. A bare pavement definition is shown (upper left), along with graphs (upper right) and dashboards (bottom) ("Dashboards Help Drive Mn/DOT Performance," http://www.dot.state.mn.us/dashboards). packed snow are acceptable and can be expected between the travel lane with bare tire tracks and sand on the remainder of wheel paths, as well as on the centre line." the lane. This is somewhat time and travel intensive and is in addition to normal storm fighting efforts. WSDOT used a single performance measure to report a level of service (LOS) rating for snow and ice control activ- PLOW ROUTES AND MATERIAL APPLICATION ities. The measure takes into consideration the traction con- DECISIONS ditions (i.e., presence of traction owing to anti-icing chem- ical, sand application, or plowing) on the travel lane road Slightly more than 80% of the respondents stated that they surface and is observed and documented during periodic field used plow routes. Four of the surveyed agencies, California, condition surveys. The traction conditions are determined by Idaho, Nevada, and Vancouver do not use plow routes. The returning to the route after a designated period of time has agencies that use plow routes use various methods to deter- past since the last plowing or sanding and examining all travel mine them including: lanes between given mileposts. Bare pavement is the condi- tion if at least 95% of the roadway surface is free of ice Staffing and performance or LOS targets; and/or snow. The roadway is considered sanded if at least Functional classification and average daily traffic; 60% of the travel lane has sand on the surface. To allow for Emergency service locations and/or transit routes; simple field analysis, 60% coverage is considered equal to a Maintenance shed or garage area; TABLE 3 ALBERTA TRANSPORTATION CONTRACT ADMINISTRATION REQUIREMENTS FOR SNOW REMOVAL AND ICE CONTROL Maximum Time to Good Segment Driving Conditions Classification Segment Characteristic Following End of Storm Class A >7,000 AADT 6 hours Class B 5,000 to 7,000 AADT 6 hours Class C 2,000 to 5,000 AADT 8 hours Note: AADT = average annual daily traffic.