TOD rules include not holding developers to a minimum parking space requirement, upping net densities for allowable units per acre, and mandating mixed use development with affordability requirements.
This last requirement about affordable housing has reportedly turned Speaker of the House Rep. Frank Chopp (D-43, Wallingford, Capitol Hill, U-District) into a fan of Nelson's bill. Chopp is strong supporter of low-income housing. His support this year is a win for environmentalists who are pushing the bill. When they pushed a similar bill last year, Chopp helped kill it (follow the tortured saga here) because his supporters in the Building Idustry Association of Washington (BIAW) didn't like it (too many building regulations.) With Chopp potentially in their corner this time around, the bill has a much better chance.
Ironically, affordable housing issues may also doom the bill. Vocal low-income housing advocate John Fox of the Seattle Displacement Coalition doesn't like the bill because he believes the density requirements lead directly to gentrification.
The local urban policy blog, HugeAssCity, strongly disagrees with Fox and pointed out that Fox overstated the impact of the proposed upzone by confusing net density (which measures units on developable land only) with gross density (which measures units over an entire area). By subbing in the higher net density number for a typically much-lower gross density number, Fox made it seem as if Seattle would become Brooklyn.
Rep. Nelson has three co-sponsors: Reps. Jamie Pedersen (D-43, Capitol Hill, Wallingford, U-District), Roger Goodman (D-45, Seattle Eastside Suburbs), and last year's prime sponsor Geoff Simpson (D-47, Covington, Black Diamond). Sen. Chris Marr (D-6, Spokane) is sponsoring a Senate version.