I just arrived back in Taipei after a trip around the island. I found the No. 2 freeway between Kaohsiung and Taipei (that is marked 3 inside a white flower on the maps and roadsigns) far better and faster than the No. 1 (Sun Yat-sen freeway, 1 on the maps and roadsigns). There’s a lot of roadworking going on along the No. 1 and it’s two lanes wide most of the way between Kaohsiung and Taichung, and these two lanes are full of trucks. The No. 3 is three lanes wide all the way with far less trucks.
It took me only 2-and-a-half hours from Kenting to Chiayi on the No. 3!
I too took the number three from Changhua to Taipei…cut my trip from Kaosiung down to about 4.5 - 5 hours.
zzzooooommm
Not so loud. We don’t want everyone jumping over. 
4 hours 30 minutes to Kenting from Taoyuan, and cruise control for most of the way… 