RideFlag is focused on offering a sustainable solution that addresses traffic congestion challenges and reduces CO2 GHGs. Misdeclaration on congested express lanes is rapidly growing in crowded cities throughout the United States and around the world. To tackle these challenges, we offer government and transportation agencies with the first-ever, easy-to-use Vehicle Occupancy Detection smartphone app. By working with partners across the United States and worldwide, RideFlag is deploying an environmentally sustainable tool that increases lane performance, mitigates HOV misdeclaration, and reduces CO2 GHGs while improving air quality.