Spur 399 is a short, limited-access spur highway located in
Collin County, Texas, and connects
State Highway 121 (SH 121) and the
US Highway 75 (US 75, Central Expressway) to
SH 5, in
McKinney
McKinney is a city in and the county seat of Collin County, Texas. It is Collin County's third-largest city, after Plano, Texas, Plano and Frisco, Texas, Frisco. A suburb of the Dallas–Fort Worth metroplex, McKinney is about north of Dallas.
...
. The highway is just over a mile long, and was originally designated in 1964, but was redesignated in 1989.
Route description
Spur 399 begins where SH 121 branches off the
Sam Rayburn Tollway
The Sam Rayburn Tollway (formerly the State Highway 121 Tollway) is a tollway operated by the North Texas Tollway Authority that runs from Grapevine to McKinney. Its frontage road are signed State Highway 121.
The original portion of the toll ...
, to merge with the Central Expressway. After the interchange, the highway passes a few empty commercial building lots, before passing the
Collin Higher Education Center to the north, and the
Medical Center of McKinney to the south. The frontage roads then, depending on the direction, merge or exit the highway. The road passes a small field, before reaching its eastern terminus, an
at-grade intersection
An intersection or an at-grade junction is a junction where two or more roads converge, diverge, meet or cross at the same height, as opposed to an interchange, which uses bridges or tunnels to separate different roads. Major intersections a ...
with SH 5.
The freeway portion of the highway contains only one exit, for US 75 south, from the eastbound lanes, but the highway's frontage roads give access to and receive access from both directions of the Central Expressway.
History
Spur 399 was designated on May 4, 1964 from US 75 to SH 5. On March 2, 1989, it was transferred to SH 121, and Spur 399 was reused for old SH 121 instead.
Extension
TXDOT has announced a plan to extend this spur 6 miles to connect with
US 380
U.S. Route 380 (US 380) is an east–west United States highway. The highway's eastern terminus is in Greenville, Texas at an intersection with Interstate 30, of which the easternmost 3–4 miles are concurrent with US 69 in a loop around ...
east of McKinney. Earliest start of the project is, quote: "earliest that construction can begin will be 2026".
Junction list
See also
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References
{{reflist
399
Transportation in Collin County, Texas