It should end then (if not before), as the number of AFVs should have reached significant numbers by then (and BEVs are forecast to be at cost parity with comparable ICEs). As it is, they had
to go to the new expiration after 3+ years program here in California, as the HOV lanes were getting clogged by SO cars with stickers which reduced HOV lanes below the federally-mandated minimum average speed, and they couldn't just keep adding to the total. I personally think it shouldn't be extended past 2023 here, but then I was never a big fan of the SO stickers in the first place, as it encourages the very behavior that causes the congestion. The upside, of course, is that it helped get more PEVs on the road, and they were absolutely dependent on that perk for sales here. After all, the stickers were originally supposed to expire at the beginning (or end, forget which now) of 2015, but were extended to boost sales, first to 1/1/2017, and then to 1/1/2019. For more: https://www.sacbee.com/news/state/california/article218596640.html
I would have preferred that they excluded the PHEVs and left the BEVs, FCEVs, and NGV's alone, since PHEVs are becoming more and more common. The whole point of the program was to encourage adoption of AFV's, and PHEVs are kinda helping that, but not fully since depending on their range and the needs of the person driving, the miles being driven may not be all that green.
(At my work every year we are required to fill out a carpool survey, mandated by the SoCal AQMD. One of the choices under commuting method (solo, carpool, bus, bicycle, etc.) is "Zero Emission Vehicle." They note that for those who choose this, the miles driven from home to work MUST be all electric, or hydrogen, or NGV. So someone driving their Prius Plug in 20 miles one way doesn't count, nor does someone driving a Volt 60 miles one way.)
Of course manufacturers whose BEV/FCEV/NGV lineups are paltry to non-existent would NEVER have agreed to that, and lobbied to not only ensure they don't get excluded, but will force turnover (and thus new car sales) by slowly phasing out older previously included vehicles from the program.
Blue Ocean 2012 Leaf SV, lost that 1st bar at 34 months/26,435 miles. Lease returned 2 months later. Final LeafStat figures: 225 Gids, 17.44 kWH, SOC 91.89%, SOH 82.36%, 69.49% HX, 54.57 Ahr, battery temp 61.8 F.
Now driving a 2015 VW eGolf SEL.