The original cost was $900 million, from bonds sold back in 1982. That only covered from Intercontinental (west of 59, Eastex) to just south of 59 (Southwest Fwy), and the Jones Toll Bridge. From there more sections were added, like the free section from 59 Eastex to I-10 East, and the south tollway and east side tollway, roughly from I-10 east southbound around to 59 southwest freeway in the 90s.The last section, costing $400 million, is due to be complete by 2011. It will cover the free section from 59 Eastex clockwise to I-10 East. There have also been addition widenings and grading changes, mostly paid for by toll revenue.The first section to open was between Katy Freeway and 59, on 4th of July weekend in 1988. There was a big party and the featured band was The Bangles. It was quite a time. I used to work on West Belt (became West Sam Houston Parkway North) in the 80s and watched them build the section between Katy Freeway and 290 in 88 and 89.
Limits I-610 to I-45 north, parallel to I-45, about 2 miles west of I-45 Length 21.6 miles Constructed Started September 1984. Section 1 opened September 1987, section 2 opened June 1988 Cost $365,925,000. (1987 dollars)