Ice Storm Service Level and Route 7
An ice storm warning is issued for 4 a.m. to 10 a.m. You supervise a 22-bus fixed-route system with 18 operators scheduled. Four operators have already called out, and two more live on a ridge road the city does not pre-treat. Route 7 is a 45-minute loop serving the regional hospital, a 180-unit senior housing complex, and a dialysis center; it has a 12 percent grade on Miller Hill. Routes 3 and 9 interline at the downtown transfer center with 15-minute headways. The paratransit contractor has 6 of 9 vehicles available. The general manager wants a recommendation by 8 p.m. tonight. The city has not declared an emergency, and the transit agency's snow plan has three levels: normal, limited, and severe. The forecast carries a half-inch of ice before dawn. The hospital has already called to ask whether its 6 a.m. shift will have service.
1. Recommend a snow-plan level and route plan for 4 a.m. to 10 a.m. Explain the trade-offs and your triggers for escalating to severe.
Read the worked answer
Recommend limited service, with Route 7 protected and detoured.
- Staffing reality: 18 scheduled minus 4 callouts minus 2 ridge-road operators at risk leaves 12 reliably available operators for 22 buses. Running normal service would require overtime and would leave no relief for delays, so a full schedule is not credible.
- Weather trigger: a half-inch of ice before dawn makes untreated grades and bridge decks the main hazard. Miller Hill's 12 percent grade is the specific risk; run Route 7 via the arterial detour even though it adds 8 to 10 minutes and may miss the closest stop to senior housing. Arrange a shuttle or staff-assisted transfer from the detour stop.
- Priority order: Route 7 first for hospital, senior housing, and dialysis access; then Routes 3 and 9 interlined at 30-minute headways to preserve downtown access; then suspend the lowest-ridership routes for the morning. Paratransit runs medical and dialysis trips first and defers non-medical trips.
- Trade-offs: this strands some riders and will draw complaints, but running full service with fatigued or unfamiliar operators on ice risks crashes, blocked buses, and a longer shutdown. The city's failure to declare an emergency does not prevent the agency from using its own snow plan.
- Escalation triggers: switch to severe if ice exceeds the forecast, if available operators fall below 10, or if two buses get stuck. Tell the hospital the 6 a.m. shift will have Route 7 service but on a detour and with possible 45 to 60 minute gaps.
2. Two operators on the ridge call and say they cannot safely drive in. What do you do, and what do you tell the general manager about the staffing risk?
Read the worked answer
Treat the ridge-road calls as safety reports, not attendance abuse.
- Ask each operator to describe the specific road conditions and whether they have chains or a safe alternate route. If they say they cannot travel safely, do not pressure them; document the call and treat it as an emergency closure. Check the CBA and leave policy before deciding pay.
- Offer practical options: meet a supervisor at a plowed park-and-ride, ride with a road-maintenance vehicle, or take a later shift if conditions improve. Do not assign them to a route that requires them to drive the untreated ridge road.
- Rebuild the schedule on 12 reliable operators and add a 10 to 15 minute recovery pad at the transfer center. Avoid mandatory overtime that pushes an operator past the agency's fatigue limit; if volunteers are needed, ask first and record rest time.
- Tell the GM: the plan is built on 12 operators, not 18; the two ridge operators may return by 8 a.m.; and if two more call out, the agency should drop to severe rather than force the schedule. The reasoning is that an operator who crashes on the way in creates the same service failure plus a safety investigation.