Cost considerations for establishing and maintaining a street sweeping program
Compared to other sediment reduction best management practices (BMPs), street sweeping is one of the most affordable options at $3 – $5 per pound of sediment removed (2013 dollars) (Hunt 2017). It is difficult to determine the exact cost of street sweeping activities for a particular municipality without site-specific information but the financial costs that should be considered are listed below (MPCA 2022b and USEPA 2021):
- Machinery purchase or rental (mechanical broom, regenerative air, or vacuum)
- Machinery maintenance (regular maintenance and repairs)
- Staff time/labor (operating and maintenance hours)
- Fuel (diesel, regular, natural gas, electric)
- Contracting services
- Operator training (equipment and background)
- Managing sweepings (disposal fees)
- Screening for reuse
- Laboratory fees (for phosphorus reduction credit and contaminants if necessary)
- Equipment storage/parking
- Program outreach/education implementation (e.g., outreach, parking enforcement, signage, email/text alerts)
- Tracking (i.e., log the number of curb-miles swept and the amount of waste collected to inform a written plan, schedule, and periodic re-evaluation)
This section summarizes the costs for various components of a street sweeping program where possible. Staffing and equipment are the largest costs for street sweeping programs (MPCA 2021b). It is important to note that before purchasing street sweeping machinery, purchasers must research the products and choose the sweepers that are right for their community (MPCA 2021a). Specific local factors should be considered including the steepness of streets or the width of streets and alleys.
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New sweeper purchases
There are three main types of street sweepers: mechanical broom, regenerative air, and vacuum. Municipalities should choose the most appropriate type based on their budget, local climate, street type, noise ordinances and major pollutants of concern (USEPA 2021). It is common for municipalities to have each type of street sweeper in their fleet. Mechanical broom sweepers are the most widely used equipment for street cleaning in the U.S. and are the most effective sweepers for areas that generate large-particle waste, like construction sites, highways and alleyways (USDOT 2022). However, regenerative air sweepers are best for deep-cleaning dry areas with small-particle debris, like parking lots and streets. Regenerative air sweepers are also the most effective for stormwater management with regard to fine particulate pickup and containment (Raymond Massey, Schwarze Industries, personal communication, September 2022).
A summary of initial purchase prices for various new street sweeper options was provided by Schwarze Industries (Raymond Massey, Schwarze Industries, personal communication, September 2022) and through a review of the 2022 Minnesota Department of Transportation’s (DOT’s) street sweeper purchase contracts. The cost for the purchase of a new street sweeper does not vary greatly between the different sweeper types (mechanical broom, regenerative air, and vacuum), with a price range of approximately $200,000 – $350,000. See Table 5 for the specific price ranges by sweeper type and source of information.
Summary of new street sweeper costs
Raymond Massey of Schwarze Industries (personal communication, September 2022) provided general information and limitations of each sweeper type. Mechanical street sweepers are available in both 3 wheel and 4-wheel configurations. The 3-wheel version has the lowest cost, but their travel capabilities are limited. The 4-wheel version allows for driving the sweeper up to highway speeds between work sites. Typical hopper capacities are 3.1 cubic yards for the 3 wheel and 5.0 – 6.0 cubic yards for the 4-wheel mechanical sweepers. The mechanical sweepers are available in both (commercial driver’s license) CDL and non-CDL packages.
The regenerative air street sweepers also come in various sizes from 4.5 cubic yard up to 9.6 cubic yard hoppers and are also available with both CDL and non-CDL packages. Vacuum street sweepers have hoppers that range from 6.5 cubic yards to 10 cubic yards and are on a CDL required vehicle.
Massey also indicated that the most effective street sweeper for stormwater management for fine particulate pickup and containment is the regenerative air sweeper. This is supported by information collected from the street sweeping case study for Edina, MN. The city determined a cost-effective frequency of street sweeping and found that upgrading current mechanical sweepers to regenerative air sweepers would increase cost-efficiency by 24%, increase load recovery of solids by 47%, and increase phosphorus recovery by 37%, while only increasing total costs by 4% (MPCA 2021a). Increasing sweeping frequency during snow-free seasons decreases the cost per curb-mile of sweeping and improves cost-efficiency. Increased sweeping frequency in priority watersheds could increase recovery of solids by 250% and recovery of phosphorus by 200%. The cost-basis lowered from about $66/curb-mile to $37/curb-mile and cost-efficiency improved from $173/lbs phosphorus (P) recovered to $152/lbs P recovered when comparing mechanical to regenerative-air sweeping (MPCA 2021a).
Cost savings can also be found by using equipment that can be converted to other uses (MPCA 2021b). For example, Jordan, MN, purchased a sweeper that can be converted to a sander and snowplow in the winter.
Street sweeper rentals
Similar to new street sweeper purchase costs, the monthly rental rates for street sweepers do not vary greatly between sweeper types, with monthly rental rates ranging from $10,000 - $16,000. Monthly rental rates for some mechanical and regenerative air street sweepers were found in a review of Minnesota DOT’s 2022 street sweeper rental contracts (Rental Equipment Contracts - MnDOT).
Minnesota DOT monthly street sweeper rental rates
MPCA’s 2021 case study interview with the City of Bloomington found that the city rented a regenerative air sweeper prior to 2021 for $12,000 per month; however, after conducting a cost-benefit analysis, the city decided that it was more efficient to buy their own sweeper. Purchasing the additional sweeper allows the city greater control over the timing of fall sweeping and allows the city to conduct additional sweeps if leaf drop is later than expected, or the streets remain snow-free longer than expected.
Used street sweepers
The purchase of used street sweepers is also an option. Costs of used street sweepers vary quite a bit depending on options and age/miles. An online search for used sweepers was conducted at the following websites: trashtrucksonline.com and machinio.com. The search found 11 mechanical broom sweepers, 7 regenerative air sweepers, and 1 vacuum sweeper for sale. There was a wide range of prices, age, and miles. The mechanical broom sweepers were all Elgin or Schwarze sweepers and ranged in price from $14,500 (2005 Elgin Pelican with unknown miles) to $217,286 (2017 Schwarze M6 Avalanche with 9,305 miles). The regenerative air sweepers were all Tymco or Elgin sweepers and ranged in price from $22,500 (2004 Elgin Crosswind with 64,821 miles) to $119,500 (2009 Tymco 600 with unknown miles). The vacuum sweeper was a 2010 Elgin Whirlwind for $59,900 (unknown miles). The oldest sweeper was a 2004 model, while the newest was a 2018.
While the purchase of a used street sweeper will save money up front, it is likely that maintenance costs will be higher than those for a new street sweeper.
Street sweeper maintenance
MPCA’s 2021 street sweeping case study interviews asked municipalities about sweeper maintenance. Rochester, MN shared that street sweeping equipment is high maintenance and breaks down often, so a lot of downtime should be expected.
The lifecycle of a sweeper depends on the type of replacement cycle the user applies. Bloomington is on a 6-year street sweeper lifecycle. They were previously on a 10-year cycle, but after conducting a cost-benefit analysis, they found that the parts tended to wear out on the regenerative air sweeper, and the sweeper was worth more as a trade-in rather than spending money on maintenance costs. Maintenance costs increased later in the cycle and by trading in the machines before they needed significant repairs, the city saved money. The sweepers are now on a rotating replacement schedule in which one sweeper is replaced each year. Bloomington currently spends approximately $35,000 per year per sweeper for maintenance on its five sweepers (3 Pelican mechanical brooms and 2 regenerative air) (Jack Distel, City of Bloomington, personal communication, November 2022).
Lakeville, MN is on a 10-year replacement cycle with regular maintenance and repair of street sweeping machinery costing approximately $50,500 annually for two mechanical broom sweepers and one vacuum sweeper (Kelly Perrine, City of Lakeville, personal communication, October 27, 2022). St. Cloud reports a 3-year average maintenance cost of $46,408, which does not include costs for fuel (Tom Zabinski, City of St. Cloud, personal communication, November 2022). The St. Cloud sweeper fleet includes three mechanical broom sweepers and two regenerative air sweepers.
Street sweeping contractors
Rather than purchasing or renting street sweepers, municipalities also have the option of contracting with an outside company to conduct street sweeping and dispose of the street sweeping waste.
The City of Lakeland, Florida (2019) conducted a study that compared in-house sweeping versus contractors. The results found that contractors were less expensive with in-house sweeping costs of $59.08 per curb mile and contract sweeping costs of $43.75 per curb mile. The city found it to be more cost effective to have contract sweepers perform the routine sweeping in the city and keep two in-house sweepers to perform downtown sweeping twice a week and perform sweeping for any special events or unscheduled tasks. Like Lakeland, Fridley, MN supplements street sweeping with their own equipment with contractors (MPCA 2021a). The contractors have been successful to date and typically accommodate the weeks chosen for sweeping by the city; however, scheduling at the proper time in the fall can be difficult. While Fridley attempts to predict leaf drop times when scheduling with their sweeping contractor, they need to make the reservation three to four weeks in advance, which can lead to missed timing when it comes to leaf drop. Sometimes the contractor needs to come out again if they miss the appropriate time for leaf drop. When this happens, the city must find additional funds to have the contractors return for additional sweeping days. They found that it often makes sense to have contractors sweep construction sites, while the city handles the sweeping with specific timing to capture leaf drop.
Bloomington, MN previously used contractors for street sweeping but now prefers to use its own staff, as city staff seem to take more ownership and pride in their work than contractors, leading to better sweeping results (MPCA 2021a). The city felt that the contractor’s equipment was old and worn out and that the contractors were focused on the area covered rather than the amount of material being picked up. They did not operate at speeds slow enough to adequately collect material as the contractors were incentivized to cover lane miles, rather than conduct sweeping for water quality benefits. Rochester, MN does not use contractors because they also feel the level of commitment is difficult with contractors (MPCA 2021a). Rochester prefers using their own equipment and staff to make the best decisions for their residents.
The biggest issue with contractors seems to be timing. The use of contractors requires reserving crews and equipment ahead of time, which can create challenges with timing for fall leaf drop collection. Leaves may fall after the contractor is scheduled to sweep leading to the need to schedule them to come back a second time. Some municipalities see the value in securing the contractors a second time, but this can lead to increased costs and uncertainty.
Staffing and training costs
Training for street sweeper operators must be included in operation and maintenance budgets (MPCA 2021b) and in the staff hours spent on street sweeping. Training options include online training, training through vendors, and in-house staff training.
The North American Power Sweeping Association (NAPSA) provides online training opportunities through its Sweeper School, which provides three different types of training modules. The training modules include a NAPSA Certified Sweeper Operator course, which varies in cost depending on whether the user is taking the municipal ($2,500), parking lot ($90) or construction ($400) course. There is also a NAPSA Certified Sweeping Manager course ($400) and a NAPSA Fleet Basics – Key Fundamentals Course ($20). The costs provided here are for non-NAPSA members. NAPSA members receive a substantial discount.
SweeperSIM is a virtual sweeper truck driving training software simulator. The software provides a realistic driving simulator for training parking lot sweeper operators in a simulated sweeping environment. The cost is $165/month for a 12-month subscription ($1,980 total) or $125/month for 12-month subscription with a 1-800-sweeper membership ($1,500 total).
Another training option is through the street sweeper vendors. When street sweepers are purchased, the vendor typically provides free training on operation and maintenance. An example is Elgin Street Sweepers, which provides several free in-person classes including field training, mechanic training, and operator training among others (Elgin Street Sweeper Training).
MPCA’s 2021 case study interviews with several Minnesota municipalities also provided insight on street sweeper training. The municipalities tend to cross train their employees, so they are trained to use multiple types of machinery, not only street sweepers. Most cities have a general city work crew that has street sweeping as part of their responsibilities, which may also include snow plowing, mowing, or tree removal.
Lakeville conducts training through their annual public works and parks meeting, in addition to more focused training sessions. Bloomington and St. Anthony Village both use experienced staff to train new staff. St. Anthony Village has 12 total city staff members, and three of them are trained for street sweeping. There is one primary street sweeping employee and two backups. Most of the training is done in-house by their primary operator who has 20 years of experience.
The time staff spends on street sweeping depends on several factors including the size of the city and how often they conduct street sweeping. Lakeville’s staff typically spends about 900 hours sweeping in the spring and 600 hours in the fall. St. Cloud spends 4,000 to 5,000 staff hours per year on street sweeping, and St. Anthony’s staff spends approximately 800 hours per year on street sweeping. Tracking staff hours helps allocate and plan staff time and shows the need for additional staff time for routine stormwater inspection and maintenance activities.
Outreach and education
Costs for a street sweeping program should also allocate funding for education and outreach regarding the benefits of street sweeping, as well as any parking restrictions related to scheduled sweeping. For instance, Lakeville’s outreach program includes social media (Twitter, Nextdoor, Instagram, Facebook, Youtube) postings on the topics of keeping leaves out of the street, street sweeper deployment timings, and purpose and promotion of the Adopt-A-Drain program (Kelly Perrine, City of Lakeville, personal communication, October 27, 2022).
St. Anthony generally uses their communications department 2-3 times per year to educate the public on their sweeping operations. St. Cloud includes street sweeping program information in the city newsletter mailed to all St. Cloud residents at the beginning of fall, and they do additional promotion and general education, including an educational sweeping video, on the city’s website - St. Cloud Street Sweeping Video (Tom Zabinski, City of St. Cloud, personal communication, November 2022).
Bloomington spends approximately $3,000/year on sweeping education and outreach (Jack Distel, City of Bloomington, personal communication, November 2022). The city includes information in its monthly resident newsletter. They generally include one or two articles on street sweeping per year. Bloomington has created some educational street sweeping videos as well.
Parking restriction notifications and signage are inexpensive forms of outreach and parking tickets are an effective way to remind residents to obey posted parking restrictions (MPCA 2021b). Parking tickets can also be used as a source of revenue for the street sweeping program.
Fuel options
There are multiple fuel types to consider when purchasing street sweepers. Fuel options include regular gasoline, diesel fuel, natural gas, and petroleum gas. Hybrid and electric street sweepers are also becoming an option. This section reviews the pros, cons, and efficiencies for diesel fuel and alternative fuels including compressed natural gas (CNG), liquefied natural gas (LNG), and liquefied petroleum gas (LPG).
Diesel fuel is typically more expensive than gasoline per gallon (NASM 2022); however, the total fuel costs for operating diesel engines are around 30 percent lower than gasoline engines (Schildgen 2018). Diesel engines are more efficient and cleaner (i.e., emit less carbon dioxide) than gasoline engines except for higher emissions of nitrogen oxides (NOx) (Ashley 2019, Rentar 2019, Schildgen 2018). Diesel fuel contains about 12% more energy per gallon than gasoline and diesel engines typically run twice as long as gasoline engines before needing major service (Schildgen 2018). Diesel engines are strong and durable and provide more torque than gasoline engines, which is necessary to operate large machinery such as street sweepers (Ashley 2019, Schildgen 2018).
Diesel fuel has traditionally been the primary fuel type used for large street sweepers, but the industry has been slowly changing to alternative fuels including CNG, LNG and LPG. Switching to alternative fuel street sweepers leads to reduced fuel costs and better efficiency, but the advantages and disadvantages of alternative fuel sources should be considered before making a purchase. Things to consider include available infrastructure, the type of engine system required, fuel storage, ease of fueling, and demands of the fleet (Trucksite 2022).
There is no difference in sweeper performance between diesel, gasoline or alternative fuel sweepers but CNG is the cleanest burning of all the fuels, producing 80% fewer greenhouse gas emissions than gasoline (Trucksite 2022). CNG also costs about 20% less than diesel fuel. Another advantage to CNG is that it is lighter than air, which means it will dissipate if there is a leak, making it a safer alternative to other fossil fuels.
Challenges associated with CNG include the infrastructure needed for stations that requires them to be located near a major natural gas pipeline. Pressurization systems are needed to store CNG, which makes them more expensive than LNG systems (Trucksite 2022). Additional challenges with using CNG include the larger size of the fuel tanks required compared to regular diesel engines (CNG occupies more space than gasoline or diesel) and the initial cost of the pumping stations. LNG is another option for an alternative fuel that is much cleaner than diesel or gasoline. While LNG is less expensive than diesel, it is more expensive than CNG, and LNG fueling stations are typically less common than CNG stations. The upside of LNG is that it can be transported over long distances while CNG cannot, and LNG requires less space than CNG (Trucksite 2022). LNG requires less than half the space that CNG does but needs to be cryogenically stored at -184° to -260° Fahrenheit (Taylor 2013). LNG also offers a density similar to gasoline and diesel fuels, which prolongs a vehicle's range and requires less fueling time. Specialized training and equipment are needed for fueling with LNG, which is not the case for CNG.
Another alternative fuel option is LPG, which is a combination of propane, propylene, butane, and butylene (Trucksite 2022). The fuel is liquefied and needs to be pressurized for storage. Like LNG, it is a cheaper and cleaner alternative to diesel and gasoline but is more expensive than CNG. However, LPG can be transported across large distances and produces more than twice the energy of natural gas, therefore, it could be more cost effective than CNG. LPG vehicles also require less maintenance than CNG vehicles. Disadvantages of LPG are that performance varies depending on composition; LPG needs to be stored in specialized tanks; and LPG is heavier than air. LPG can settle in low-lying spots, which creates the risk of explosions when indoors. It is best to keep LPG vehicles in outdoor parking areas.
Annual street sweeping costs from Minnesota case studies
MPCA’s street sweeping case studies for cities in Minnesota collected multiple items of interest related to street sweeping including annual sweeping costs (MPCA 2021a). The case studies showed widely variable costs for local sweeping programs that ranged from $45,000 for smaller cities to $850,000 for larger urban areas. The median street sweeping cost was $94/curb mile while the average cost was $487/curb mile. Cost per curb mile ranged from $7 to $2,485/mile but was $34 and $38/mile for the cities of Mankato and St. Cloud, respectively, which where the best documented case studies. These costs are similar to a study in Prior Lake ($20-29/mile) (Kalinosky et al. 2014). The cost information provided by the cities typically did not include equipment costs but usually included disposal costs. The summary of annual costs reported by each city is presented in Table 7.