ESPN's Bob Pockrass has examined International Speedway Corporation's 2018 Annual Report and calculated the number of seats removed at several of ISC's 12 tracks:
The numbers are down dramatically company wide over their peak:
For ISC peak was 2007 at 1.1 million. Now at 683,000. https://twitter.com/bobpockrass/status/1088938409035550723— Bob Pockrass (@bobpockrass) January 25, 2019
However, the reduced seating primarily comes as tracks try new ways to attract fans:
Many tracks have taken out seats for more "social" settings or areas where people can move around and watch. The Phoenix and Richmond infields offer new looks. https://twitter.com/bobpockrass/status/1088939115838623750— Bob Pockrass (@bobpockrass) January 25, 2019
ISC's press release about fiscal 2018 results can be found here: International Speedway Corporation Reports Financial Results for the Fourth Quarter and Full-Year of Fiscal 2018
Note: Additional track seating data can be found Jayski's old Race Track Seating Capacity (and attendance) page.
AND at Speedway Motorsports' Las Vegas track: Las Vegas Motor Speedway apparently is shrinking again.
A Friday internet report detailing additional downsizing at International Speedway's NASCAR tracks prompted a Twitter response from a race fan indicating LVMS is doing the same.
"Check out @LV Motor Speedway had to relocate my seats," wrote Jesse@American83. An accompanying image, which appeared to be from a ticket brochure, said LVMS was removing odd-numbered rows from several sections in the main grandstand to install railings for food and drink.
A speedway source said changes still were being discussed and wouldn't be made until the fall Cup Series race.
Seating capacity at the 1.5-mile oval, one of eight NASCAR tracks owned by Speedway Motorsports, was significantly reduced last year, leaving around 80,000 permanent seats. During NASCAR's heyday, LVMS regularly drew race day crowds estimated at 140,000.
--- Las Vegas Review-Journal ---