Missouri City residents in Sienna will get new road connections to FM 521 and a wider Sienna Parkway under a development agreement the City Council approved Sept. 21.

The deal with Toll-GTIS Property Owner, LLC (Toll Brothers) and Sienna Municipal Utility District No. 5 (MUD 5) commits up to $10 million from MUD 5 toward widening Sienna Parkway from four lanes to six between Steep Bank Trace and Scanlan Trace North. That stretch includes the railroad crossing.

The agreement sets hard deadlines. Four lanes of Sienna Parkway Phase 7 must be finished by Dec. 31, 2027, completing a continuous four-lane route from Waters Lake Boulevard to FM 521, according to a city press release. Sienna Lakes Drive Phases 4 and 5 must also be done by Dec. 31, 2027, extending Sienna Lakes Drive from Park Crossing to FM 521. The exact connection point at FM 521 has not been finalized.

A separate project to widen Sienna Parkway over the railroad tracks from four to six lanes, including the bridge, is projected for completion in 2029, according to the city's Sienna Mobility Improvements page.

MUD 5's $10 million contribution will be spread over three years: $2 million in 2027 and $4 million each in 2028 and 2029, Community Impact Newspaper first reported.

In return, Toll Brothers will build designated roadway projects, fund traffic-related work tied to its development and provide right of way for future mobility corridors.

The agreement also creates a path for a potential north-south connection between Park Crossing Drive and One Oak Chase Road. That link would provide another route into and out of Sienna but crosses multiple jurisdictions. It remains subject to right-of-way acquisition, Fort Bend County requirements, City of Arcola approvals and city authorization to proceed.

City Attorney E. Joyce Iyamu told the council that city staff had not approved new Sienna developments because they recommended fixing traffic circulation first, Community Impact reported. Public Works Director Mustafa Albassam said the road improvements will allow developers to resume building homes in the area.

"Anticipating what the future will bring, you need to have capacity and alternate routes for the residents to use," Albassam told Community Impact in a Sept. 25 article about the agreement.

Council also approved an amendment to the Major Thoroughfare Plan that will remove two previously proposed north-south routes in Sienna once the specified road segments are built. The city's Planning and Zoning Commission had recommended the thoroughfare plan changes in a 6-0 vote on May 13. At that meeting, multiple residents spoke against the proposed revisions, citing concerns about property values, traffic on narrow roads, flooding and wetlands impacts.

On June 10, the commission voted to disapprove several Sienna development applications, including revised concept plans for Sienna 4B, 4C and 5B, because each would create significant traffic impacts and fail to meet the city's capacity standards.

The first construction deadline falls Dec. 31, 2027. Residents can track progress on the city's Sienna Mobility Improvements page.