50% of what? Do you mean emissions will be cut 50% from today’s level?

Our primary metric is vehicle efficency – with a target to cut vehicle fuel use (and CO2) per kilometer by 50% from today’s level, on average for all cars on the planet – by 2050. Our broader objective is to see total vehicle emissions 50% lower in 2050 than they would otherwise be if we don’t accelerate our efforts to improve vehicle fuel economy.  If we follow a business as usual path that accounts for existing agreed fuel economy standards and a natural rate of technological change we expect to see fuel use and emissions roughly double between now and 2050. If we do everything we can to get cost effective technologies fully into the market quickly, aided for example by tough long term standards, we can cut 2050 emissions in half, keeping them capped at today’s level.