Why Does the Engine Turn on at +62 MPH?

It is your opinion and seems to be your established position. Do you have any fact to support your conjecture?

SAE articles for the development PHV were published before Gen3 was released. Toyota even submitted the emission data to EPA as 2010 PHV model and EPA approved it as AT-PZEV. CARB even listed 2010 PiP as the qualified plugin for the new green HOV sticker.

Eligible Vehicles - Single Occupant Carpool Lane Use Stickers

From what I pieced together, PHV model was supposed to launch at the same time as Gen3 but Toyota ran into problem with their Lithium battery. It was too expensive to manufacture due to that being the last stage of their process. They have updated their process so, production cost is studied while validating technology.

2+ years was delayed due to Lithium battery. They produced about 50 to study real world data and what we know as pre-production model. They bought Sanyo battery business and used it in the production PiP.

Gen3 also included electric water pump and exhaust heat recovery system both beneficial for PHV. A regular Prius is underutilizing the electric propulsion system with NiMH battery as it was designed with a more powerful Lithium PHV battery in mind.

Not only in Japan. As I understand, 100 km/h is also the limit in most of Europe. Remember 1974 national speed limit (55 mph) in US was set to improve fuel economy.

Gen3 was designed for North American market due to Gen2 success here. It was tuned to be more efficient at higher highway speed than Gen2. Gen3 achieved it by employing larger gas engine that revs at lower rpm for the same speed.

If you follow all these reasons and logics, what you are trying to insinuate does not make sense.

 

Yet his screen name claims it is not about the money.

Which is it?

NS4 (next gen PiP) will have the next generation of HSD so I would expect to see bigger changes. Interesting times ahead, hopefully the reveal with Gen4!

 

I still do not understand how they could miss the EPA test cycle that probably cost them dearly.
Anyone with a PIP knows there is no problem of regularly getting 11-18 miles all EV (depending on weather) but the sticker...
On the other hand, as of today they have not rolled out the PIP to all states, so maybe it is simply conservative engineering and production limitations?

 

Once Toyota specifies a certain # of miles in EV, they'll have to deal with all of those people who don't hit those marks - and for any number of stupid reasons. Easier to do it the way they did and have owners be "pleasantly surprised" when they regularly hit 12-18 miles in EV mode. Besides, those who've had their cars for almost two years now already know that miles in EV are heavily dependent on a number of variables - not all of which can be driver controlled.

 

I'm actually been able to EV drive to 64mph...

Galaxy Note 10.1 ? Pro

 

Dash displays 64 mph while OBD2 reports 62 mph (actual).