Urban road maintenance is crucial for city image and resident quality of life. Street sweepers, as primary cleaning equipment, significantly impact cleaning effectiveness. Currently, two main sweeper types—brush and vacuum—each have limitations during peak leaf seasons. This study examines structural characteristics and performance of sweepers used by Tokyo's National Highway Office to identify optimization opportunities.

Tokyo's highway maintenance primarily uses three sweeper types: vacuum recirculation, four-wheel brush, and three-wheel brush models, each with distinct structural features affecting performance.

These units use powerful suction through blowers to collect debris. While effective for fine particles, their design struggles with larger items like leaves and branches due to intake port limitations and frequent clogging. The truck-mounted four-wheel chassis supports the vacuum system.

Using rotating brushes to direct debris into collection bins, these excel with larger objects but often scatter leaves rather than collecting them. Their truck chassis design includes mounted brushes that generate dust and show limited effectiveness for fine particles.

Operating similarly to four-wheel models but with specialized tri-wheel chassis, these offer superior maneuverability in tight spaces like sidewalks. However, their discontinued status makes maintenance challenging.

Tokyo's highway office implemented two key modifications to vacuum sweepers for leaf collection:

Original rubber flaps designed to prevent dust scattering were shortened to reduce leaf collection interference while maintaining dust control.

Adjustable intake ports were raised slightly to prevent leaf accumulation while maintaining suction efficiency.

Field tests revealed:

• Modified vacuum sweepers showed partial leaf collection success but left residual debris
• Four-wheel brush models often scattered leaves, creating secondary pollution
• Three-wheel brush units demonstrated relatively better performance despite operational limitations

Vacuum models face leaf clogging in intake pipes, while brush types struggle with conveyor jams from leaves and branches. The discontinued three-wheel design, while effective, presents sustainability challenges.

Tests showed water spraying had negligible effect on leaf collection efficiency.

Key findings suggest:

• Vacuum sweepers require additional modifications for comprehensive leaf collection
• Four-wheel brush models are unsuitable for leaf collection without significant redesign
• Three-wheel brush designs show promise but face availability issues

Recommended optimizations include:

• Adding auxiliary brushes to vacuum models
• Testing alternative intake materials
• Increasing blower capacity and intake dimensions
• Redesigning conveyor systems in brush models

Potential research areas include:

• Material science for anti-adhesion intake surfaces
• Brush design optimization
• Blower system enhancements
• Smart sensing technologies for adaptive cleaning

Implementation requires evaluation of:

• Physical space for auxiliary components
• Power system capacities
• Material durability and cost factors
• Vehicle stability with modified designs

With three-wheel sweepers being phased out, optimizing existing vacuum models presents the most viable path forward for efficient autumn leaf collection in urban maintenance operations.