GIS helps put trash route changes on track

By Claire E. HouseGCN StaffCareful planning, exploiting institutional memory and tuning a geographic information system software package prepared Fairfax County, Va., for a trash route overhaul that officials expect will bring big savings and improve service.The county's Geographic Information Systems Department teamed with its Solid Waste Collection and Recycling Department last February to develop a system that has helped the county optimize routes for the 38,400 residences its refuse collection trucks serve weekly.'We're basically filling up the day more efficiently,' Solid Waste and Recycling assistant director Randy Hancock said.Previously, 16 crews each ran one trash route daily, then reran the route to collect yard waste. During the first three months of the year when yard waste wasn't collected, crews were simply done for the day when they completed their trash routes'sometimes by noon. Crews sometimes cheated and threw yard waste on top of refuse, which could draw fines for the county. Some routes took less time to complete than others, so crews on those routes had an unfair time advantage.RouteSmart 3.65 from RouteSmart Technologies Inc. of Columbia, Md., helped the system team develop a better setup.'It enabled us to create even routes based on time, whereas before [the department] would look at the number of homes'which isn't a good indicator of how long a route's going to take,' GIS spatial analyst and application development team leader Brendan Ford said.Now, 10 trash crews run one full route daily, and five separate yard waste crews run one route daily from April through December. The new routes will save the county an estimated $200,000 annually, Ford said.RouteSmart runs as an extension of ArcView 3.2 GIS software from Environmental Systems Research Institute of Redlands, Calif., under Microsoft Windows NT 4.0. Ford recommends at least a 500-MHz Pentium with 'plenty of disk space because there are a lot of files associated with it,' he said.The team began the pilot in February last year, altering Monday's routes only. In December, it began calculating routes for the rest of the weekdays, which the trucks started running in May.The system team tapped the county's tax assessment database for a list of addresses that receive trash collection service from the county. The GIS Department then matched the addresses with street centerline data, a process called 'georeferencing.' The centerline data layer came from ESRI ArcInfo, which RouteSmart initially ran under and which exchanges data with the newer ArcView part of the system.Armed with stopwatches, Solid Waste and Recycling staff members collected all kinds of field data to plug into the system. For example, they clocked the time it takes a truck to stop, pick up the refuse, load it up and get moving again; the speed at which a truck travels between close houses during collection; the time it takes the trucks to drop off a full load at the landfill; and morning prep time.Staff members looked at landfill records to calculate average load weight and determine how many houses could be collected before the truck had to head off to the landfill. They entered data on whether collection points were townhouses, which are quicker to collect trash from, or detached homes.Staff members also attached attributes to each street regarding speed limit, one-way status and whether a street was busy enough to require pickup one side at a time.Each step of the way, the team generated maps and asked Solid Waste and Recycling superintendent and institutional guru John Childress to look them over. Field supervisors and drivers also looked over the maps to point out geographic inaccuracies and undesirable situations such as left turns against heavy rush hour traffic.'In the first year of this project, we probably spent four or five months just editing our street centerline and customer location data layers,' Ford said.Ford and a Solid Waste and Recycling staff members then drove through the routes and made sure that every street on the maps was actually there. Ford had spoken with some other RouteSmart users who hadn't checked the centerline data and had found that their new maps weren't too popular with crews that were directed down nonexistent streets.RouteSmart then calculated the best routes based on timing considerations. The team tweaked the plans a bit by manually swapping some streets between routes, Ford said.The team has developed a set of daily field maps and directions for crews, as well as central overview route maps for each day. It tried to make the new routes as easy as possible by assigning the drivers familiar areas, Ford said.Although drivers experienced with a route will come to know it like the backs of their hands, the maps and step-by-step directions that RouteSmart helped generate will be a big plus for new and substitute drivers, Hancock said.The county also did not change any resident's pickup days. Some pickup time changes were inevitable, however, which required the county to mail notifications.'We have a lot of customers that set their clocks by when the crews come by. If it has been 6:15 for 10 years and now it's 6:30, they start calling and saying they were missed,' Hancock said.'Or the truck will come earlier, and the trash won't be set out,' Ford said.The county also made it clear to drivers that they don't have to follow the routes exactly as the maps lay them out.'You can run it the way you want to, but we're not paying you a lot of overtime to be out there all day,' Ford said.Since the pilot, the county has developed a parcel maintenance application that will procedurally incorporate property and street centerline data changes. Staff members will be able to flag any changes within a sanitation zone.The team is also developing a customer service application that ties into the route system.