Balance Speed And Safety For Street-Smart Routing

Dianne De Roze and Debbie Miller

With a constantly shifting population base and increased waste stream fragmentation, close evaluation of collection systems is needed to keep costs down. Communities that haven't evaluated collection routes within the last two years likely are not operating as efficiently as possible.

Remember, effective route management can reduce labor and vehicle needs, balance workloads, reduce overtime demands and allow for workload adjustments during periods of seasonal waste variation.

The design has two interconnecting phases: macro and micro. Macro routing focuses on the entire geographic area to be served by all vehicles and by each individual crew in one collection day, while micro routing hones in on each individual vehicle's specific path.

Many communities use macro routing to determine basic route size and operation region, but let the drivers determine the exact route based on their daily experiences. In small communities, this method may be sufficient. However, there are several key benefits of micro routing:

* minimizes accidents by limiting dangerous left turns;

* increases customer satisfaction by ensuring that collection crews will consistently service each route segment;

* minimizes property and personal injury resulting from reversing vehicles down streets;

* minimizes productivity loss due to absenteeism since substitute drivers may lose time while calculating the best path route; and

* helps the route manager predict, with reasonable accuracy, where the driver will be at a given time.

Micro routing also allows the route manager to compensate for construction and heavy traffic. Despite the planning and research involved, micro routing enables the route manager to maximize crew safety and time efficiency.

The goal of macro and micro route design is a balance between the number of households served per route, weight collected, time requirements and distance between customers and facilities. The most overlooked basic data needs required of both manual and computer routing include the number of households served (total and per route) and the average set-out rate per route/per collection day.

Route Efficiency "How efficient is my routing operation?" The question seems elementary, but is often taken for granted. A useful check is to replace a regular driver for several weeks and compare his usual time to that of the substitute.

A large time discrepancy may indicate inefficiency in the route design or a problem with the regular driver or the collection vehicle. Productivity standards should consider location conditions, work rules, waste stream and crew and vehicle configurations.

Many systems have implemented incentive programs to encourage quick route completion. Some of these programs permit crews to go home after the completion of their "task," but others allow them to leave only if there are no equipment breakdowns on other routes. In the event of an equipment breakdown on another route, all crews are expected to help.

Unfortunately, such incentive programs can open the door to crew complaints of uneven workloads. While it is often difficult to ferret out the legitimate complaints, one way to assess legitimacy is to have the crews switch routes every six months. This will uncover any workload inequity.

Incentive programs tend to place emphasis on collection speed, which may indirectly encourage workers to compromise their safety by improper operating and lifting procedures. Effective operator training is re-quired to instill a balance between speed and safe practices.

The Technology Boon Computers are ushering in a new route management era. As budget-conscious haulers scrutinize their current method, the old manual formula of driver know-how and maps is being pushed aside in favor of technology.

Both manual and computer routing require a time investment in order to collect background data (see chart). There are several computer routing software packages on the market, but each require a considerable amount of information to be entered.

Is computerized routing worth this trouble? While the capital and time required for computerization may seem immediately daunting and expensive, the process, amortized over time, may be significantly cheaper than traditional routing and billing management systems.

Once the information is in the system, the computer software can provide road maps of the most efficient routes, including preferences for right-hand turns and heavy traffic locations. Individual customer information can be added, and daily print-outs can alert drivers to customers with special needs.

The foundation of computer routing is Geographic Informa-tion System (GIS) street maps. These "center-line" maps are digitized representations of every street in a jurisdiction with line segments representing every block. The map database also might indicate ad-dress ranges per block, paved surfaces, road weight limitations or turning re-strictions.

Many larger local governments are developing their own GIS systems which incorporate MSW management characteristics with water/ sewer and utility poles. Centerline map databases also are available from commercial vendors for almost every county in the nation. Firms such as E-TAK Navigation Tech-nologies, Menlo Park, Calif., and Geographic Data Technologies, Lebanon, N.H., produce these digitized map databases at costs that range from approximately $650 to $2,500 per county.

Computer-assisted routing also requires customer databases, often available through tax assessors' offices or a utility billing system. Some software packages even can incorporate satellite photos with enough resolution to see individual households. These databases can be folded into the GIS software to create a package that will track specific customer information within the routing framework.

The software's cost range varies, depending on your desired outputs. Low-end systems can provide basic route tracking and billing assistance for less than $5,000, while sophisticated software costs more (starting around $40,000 typically).

Not Fancy, But Not Easy Evaluating and implementing new route management strategies can be an arduous process, but the results are worth the effort. The first step is defining collection service areas that are well-balanced. As a starting point, consider total customers served, multiplied by collections per week, divided by collection days. Make sure you know the number of customers served in each region; weekly collection frequencies; and natural boundaries. After these factors have been determined, divide the collection service areas into individual routes (work per truck/crew per day). In this step, you should know:

* house/customer count data on a block-by-block basis;

* vacancy/occupancy;

* available collection vehicles;

* average set-out rates (and differences by region, if known);

* average weights per set-out (and differences by region, if known);

* time required per stop (including travel between customers);

* non-productive time (to route, to disposal/processing locations, to vehicle yard, etc.);

* maximum customers that can reasonably be served by each type of vehicle/crew combination, account-ing for differences in collected materials, vehicle capacity, compaction ratios, vehicle age/reliability, and crew size.

Next, design path routes, using EPA heuristic routing guidelines, keeping in mind the location of one-way streets, dead-ends and other topographic- or traffic-related features that affect heuristic route design. Finally, drive routes to test for practicality.

Tale of Two Cities In 1992, Norman, Okla., tried to evaluate their residential solid waste (RSW) collection system's productivity. The rate of operating cost in-creases was projected to create a deficit for the sanitation department, and increases in charges to the customer could only be authorized by a public referendum. The increased political and internal pressure re-sulted in the union and solid waste management department developing cost-cutting strategies.

Improvements in route balance and crew productivity were key to solving Norman's fiscal dilemma. By manually restructuring routes and establishing a minimum workday of seven hours per crew, the city in-creased productivity, reduced the number of crews and vehicles needed and saved money. It estimated re-routing savings to be approximately $452,000 per year (see chart above).

In Charlotte, N.C., computer-assisted routing is one way that the city is maintaining a competitive posture and controlling costs in a rapidly-changing environment. In the past several years, its RSW collection systems have undergone significant modifications, including:

* switching from rear door to curb-side collection;

* implementing fully automated RSW collection;

* reducing RSW collection frequency from twice- to once-per-week;

* privatizing about 25 percent of the RSW collection routes; and

* experimenting with changes in collection work day schedules (e.g., five 8-hour days per week versus four 10-hour days per week).

To help optimize route design and maintain balance, Charlotte invested in a software package from Route-Smart, Columbia, Md. Its initial purchase price was approximately $37,000. In addition, city staff estimate that the equivalent of approximately $38,000 in staff time was required to collect and input data needed for the route design algorithms to function appropriately.

The city estimates that the system saved them more than $26,000 in labor costs compared to staff time that would have been required to re-route the city's RSW fleet during its first application. The $26,000 represents savings from the act of routing only, such as the difference between the labor costs required to conduct a manual re-routing of the city compared to the labor needed for computer-assisted routing.

The $26,000 does not cover additional savings associated with route optimization. After using the software, nine routes were eliminated. In addition, route productivity im-proved 26 percent for RSW routes; 71 percent for recyclables routes and 3 percent for yard waste routes.

The Bottom Line Routing management is a necessity, not a luxury. Whether you decide to remain with manual routing or upgrade to computer routing, a significant amount of time and effort needs to be expended to maximize efficiency and potentially reduce collection costs. However, the possibility of cost reduction and increased customer service will pay off in the long run.

Manual routing is still the most common approach. In 1974, the U.S. Environmental Protection Agency (U.S. EPA) produced the following heuristic routing guidelines to help route managers design the most efficient collection paths. The drivers/operators still need to test these "paper" paths for practicality under actual field conditions.

* Don't fragment or overlap routes.

* Equalize workloads; collection plus handling times should be reasonably constant.

* Start routes close to the vehicle yard.

* Avoid heavily-traveled streets during rush hours.

* Start one-way streets near the upper end; use a looping process.

* Minimize left turns.

* On hills, collect both street sides as vehicle is moving downhill.

* Start at higher elevations and move downhill.

* When collecting from one side of the street at a time, route with clockwise turns around blocks; right turns are safer, especially for right-hand-drive vehicles.

* When collecting both sides of the street at the same time, route with long, straight paths across the grid before looping clockwise.

Source: Heuristic Routing for Solid Waste Collection Vehicles, U.S. EPA, 1974.