"The hope is that average road speeds can be reduced, improving fuel consumption and cutting congestion."

I've got bad news for the developer of this product. Unless the government makes it mandatory, the product is going nowhere. Unless consumers see a clear path between the product and their goal, they won't adopt it. While improved fuel consumption is a draw, pairing it with reduced speed is a death knell. Drives can already improve fuel efficiency by slowing down. Even as little as 5 MPH can have a significant impact on fuel efficiency, yet the majority of drivers continue at a hurried pace? Why is that? Because priority #1 is getting where we're going, and we want to get there as quickly as we can.