Anchor: #i1005943

Section 5: Clear Zones

Anchor: #i1005970

Clear Zone Specifications

Anchor: #i1010615Table 2-12 from TxDOT Roadway Design Manual

Location

Functional Classification

Design Speed (mph)

Avg. Daily Traffic

Clear Zone Width (ft)3,4,5

Minimum

Desirable

Rural

Freeways

All

All

30 (16 for ramps)

Rural

Arterial

All

0 - 750

750 - 1500

>1500

10

16

30

16

30

--

Rural

Collector

> 50

All

Use above rural arterial criteria.

Rural

Collector

<45

All

10

--

Rural

Local

All

All

10

--

Suburban

All

All

<8,000

106

106

Suburban

All

All

8,000 - 12,000

106

206

Suburban

All

All

12,000 - 16,000

106

256

Suburban

All

All

>16,000

206

306

Urban

Freeways

All

All

30 (16 for ramps)

Urban

All (Curbed)

> 50

All

Use above suburban criteria insofar as available border width permits.

Urban

All (Curbed)

< 45

All

4 from curb face

6

Urban

All (Uncurbed)

> 50

All

Use above suburban criteria.

Urban

All (Uncurbed)

< 45

All

10

--

1 Because of the need for specific placement to assist traffic operations, devices such as traffic signal supports, railroad signal/warning device supports, and controller cabinets are excluded from clear zone requirements. However, these devices should be located as far from the travel lanes as practical. Other non-breakaway devices should be located outside the prescribed clear zone or these devices should be protected with barrier.

2Average ADT over project life, i.e., 0.5 (present ADT plus future ADT). Use total ADT on two-way roadways and directional ADT on one-way roadways.

3 Without barrier or other safety treatment of appurtenances.

4 Measured from edge of travel lane for all cut sections and for all fill sections where side slopes are 1V:4H or flatter. Where fill slopes are steeper than 1V:4H it is desirable to provide a 10 ft area free of obstacles beyond the toe of slope.

5 Desirable, rather than minimum, values should be used where feasible.

6 Purchase of 5 ft or less of additional right-of-way strictly for satisfying clear zone provisions is not required.



Previous page  Next page   Title page