Clean Transportation, Accessible for All

Proterra has partnered with Optimal-EV to develop the S1LF, the first all-electric low-floor cutaway shuttle bus for the North American market. Built on a Ford E450 chassis platform that has been fully optimized for the vehicle body, the S1LF is powered by Proterra’s advanced EV technology that’s been proven through 20+ million service miles. With 113 kWh of energy storage capacity and more than 125 miles of driving range, the S1LF is ideal for zero-emission, easily accessible transportation.

Clean Transportation

Powered 100% by Proterra battery-electric technology, the S1LF reduces emissions and improves air quality in the communities it serves.

Proven Technology

The S1LF offers fleet operators Optimal’s demonstrated expertise in automotive design, computer aided engineering (CAE) optimization, and validation — combined with proven EV technology from Proterra.

Accessible Design

Optimal’s low-floor design allows for ultra-low 11-inch step-in height and quick deployment of an ADA-compliant accessibility ramp, enabling easy access for all passengers.

The Proterra Battery

Battery Small


  • Active thermal management software for optimal charging and operation
  • Energy reserve dynamically adjusts over time for maximum performance
  • Sensors throughout pack deliver continuous monitoring and diagnostics


  • Strong and ruggedized materials designed to withstand the toughest conditions
  • Battery architecture features built-in safety mechanisms
  • Rigorous vehicle testing and validation programs for highest standards of safety


  • Compact design enables industry-leading energy density
  • Efficient energy storage enables record-breaking range capabilities
  • Consistent temperature control maximizes battery life in any climate
Power Electronics Charger 75 Kw

Flexible, High-Power Charging

The S1LF electric shuttle bus works with standardized chargers such as Proterra’s high-power charging systems designed for commercial applications. The S1LF can fully charge in two hours with a 60 kW DC fast charger.

Standardized Technology

Industry-standard charging technology seamlessly connects with your electric shuttle buses and other electric vehicles in your facilities with SAE J1772 CCS DC fast charging.

Modular and Scalable

Each Proterra Power Control System can be paired with up to four dispensers, reducing charger costs per bus as you scale and enabling automated, sequential vehicle charging.

Turn-Key Infrastructure

Proterra offers a turn-key approach to your charging infrastructure, including design, build, financing, operations, maintenance, and energy optimization.