Appendix B: Minimum Design Criteria for Projects Requiring a Design Waiver

Table B-1: 4R Curb Parking Lane Width (Minimum)

Table B-2: 4R Speed Change Lane Width (Minimum)

Table B-3: 4R Length of Speed Change Lanes (Minimum)

Table B-4: 4R Curb Offset (Minimum)

Table B-5: 4R Bridge Width (Minimum)

Table B-6: 4R Median Width (Minimum)

Table B-7: 4R Clear Zone (Minimum)

Table B-8: 4R Lateral Offset to Obstructions (Minimum)

Table B-9: 4R Railroad Overpass Geometrics

Table B-10: 4R Sag Vertical Curve Length

¹

Table B-11: 4R Superelevation (Non-rate elements)

Table B-12: 4R Guardrail Length

¹

Table B-13: TxDOT's 4R Non-Controlling Criteria for Bicycle Facilities (Minimum)

Table B-14: 3R Design Speed (Minimum)

¹

Table B-15: 3R Horizontal Curve Radius (Minimum)

Table B-16: 3R Stopping Sight Distance (SSD) (Minimum)¹

Table B-17: 3R Maximum Grade

¹

Table B-18: 3R Superelevation (Non-rate elements)

¹

Table B-19: Bridge Width¹

Table B-20: Deficient Bridge Rail

¹

Table B-21: 3R Clear Zone (Minimum)¹

Table B-22: 3R Speed Change Lane Width (Minimum)

¹

Table B-23: 3R Length of Speed Change Lanes (Minimum)

¹

Table B-24: 3R Curbside Parking Lane Width (Minimum)

¹

Table B-25: 3R Guardrail Length^1,2

Table B-26: 3R Sag Vertical Curve Length

¹

**Table B-1: 4R Curb Parking Lane Width (Minimum)**
Facility Type	Additional Factors	Width	Reference
Arterials	Rural Town Urban Core Urban	10-ft^1,3	TxDOT Criteria
Collectors	Rural Town Urban Core Urban	8-ft^1,3	TxDOT Criteria
Local	Rural Town Urban Core Urban	8-ft1²	TxDOT Criteria
Frontage Roads	See Section 4.10.16.4		TxDOT Criteria
Notes:
1. Where there is no demand for a future through lane, 8-ft minimum may be used.
2. In non-commercial and non-industrial areas, 7-ft minimum may be used
3. If bicyclists and parked vehicles need to be accommodated 12 to 14 -ft widths should be used.

**Table B-2: 4R Speed Change Lane Width (Minimum)**
Facility Type	Additional Factors	Width	Reference
Freeways	Rural Suburban Urban Core Urban	12-ft¹
Arterials	Rural Rural Town Suburban Urban Core Urban	10-ft	TxDOT Criteria
Collectors	Rural Rural Town Suburban Urban Core Urban	10-ft	TxDOT Criteria
Local	Rural Town Suburban Urban Core Urban	9-ft	TxDOT Criteria
Two-way Left Turns	See Table 4-22		TxDOT Criteria
Frontage Roads	Use Collector Data		TxDOT Criteria
Notes:
1. 12-ft lane + 6-ft minimum adjacent shoulder

**Table B-3: 4R Length of Speed Change Lanes (Minimum)**
Facility Type	Additional Factors	Reference
Arterials	Rural Rural Town Suburban Urban Core Urban	TxDOT Criteria See Table 4-14
Collectors	Rural Rural Town Suburban Urban Core Urban	TxDOT Criteria See Table 4-14
Local	Rural Town Suburban Urban Core Urban	TxDOT Criteria See Table 4-14
Frontage Roads	Use Collector Data	TxDOT Criteria

**Table B-4: 4R Curb Offset (Minimum)**
Facility Type	Additional Factors	Offset	Reference
Arterials Collectors Local	Rural Town Suburban Urban Core Urban	1-ft	TxDOT Criteria
Frontage Roads	Use Collector Data		TxDOT Criteria

**Table B-5: 4R Bridge Width (Minimum)**
Facility Type	Reference
Freeway Arterial Collector Local	See TxDOT Bridge Project Development Manual

**Table B-6: 4R Median Width (Minimum)**
Facility Type	Additional Factors	Median Width	Reference
Freeways	---	----	See chapter 8 section 8.1.9 for freeway median guidance
Arterials Collectors Local	Rural: Flush Depressed	4-ft 48-ft	TxDOT Criteria
Arterials Collectors Local	Rural: Suburban: Urban Core: Urban : Raised Raised W/ Pedestrian Refuge Flush Two-Way Left Turn Lanes: DS ≤ 40 mph DS = 45 or 50 mph DS > 50 mph	4-ft 6-ft¹ 4-ft ---- 11-ft 12-ft 14-ft	TxDOT Criteria
Notes:
1. ). If pedestrians are expected to cross the divider, then the divider should be a minimum of 5-ft wide (normal to direction of pedestrian travel) to accommodate a cut-through landing or refuge area that is at least 5-ft x 6-ft.

**Table B-7: 4R Clear Zone (Minimum)**
Facility Type	Additional Factors	Clear Zone Width	Reference
Freeways	Rural Suburban	30-ft	TxDOT Criteria
Arterials	Rural: ADT < 750 ADT ≥ 750	16-ft 30-ft	TxDOT Criteria
	Suburban: ADT ≤ 16000 ADT > 16000	10-ft 20-ft
	Urban: Curbed (DS ≥ 50 MPH) Uncurbed (DS ≥ 50 MPH)	Use Suburban Criteria
	Rural Town, Urban, Urban Core: Curbed (DS ≤ 45 MPH) Uncurbed (DS ≤ 45 MPH)	4-ft from FOC 10-ft
Collector	Rural: DS ≤ 45 MPH DS ≥ 50 MPH (ADT ≤ 750) DS ≥ 50 MPH (ADT > 750)	10-ft 16-ft 30-ft	TxDOT Criteria
	Suburban: ADT ≤ 16000 ADT > 16000	10-ft 20-ft
	Urban: Curbed (DS ≥ 50 MPH) Uncurbed (DS ≥ 50 MPH)	Use Suburban Criteria
	Rural Town, Urban, Urban Core: Curbed (DS ≤ 45 MPH) Uncurbed (DS ≤ 45 MPH)	4-ft from FOC 10-ft
Local Roadways	Rural	10-ft	TxDOT Criteria
	Suburban: ADT ≤ 16000 ADT > 16000	10-ft 20-ft
	Urban: Curbed (DS ≥ 50 MPH) Uncurbed (DS ≥ 50 MPH)	Use Suburban Criteria
	Rural Town, Urban, Urban Core: Curbed (DS ≤ 45 MPH) Uncurbed (DS ≤ 45 MPH)	4-ft from FOC 10-ft
Ramps and Direct Connectors	Rural Suburban Urban Core Urban	16-ft	TxDOT Criteria
Collector-Distributor Roads	Rural Suburban Urban Core Urban	16-ft	TxDOT Criteria
Frontage Roads	Use Collector Criteria
Notes:
1. "DS" stands for Design Speed

**Table B-8: 4R Lateral Offset to Obstructions (Minimum)**
Facility Type	Condition	Offset	Reference
Freeway Arterial Collector Local	All Contexts: Curb¹ Barrier²	1.5-ft 1-ft	TxDOT Criteria
Notes:
1. Measured from nominal face of curb.
2. Measured from toe of barrier.

**Table B-9: 4R Railroad Overpass Geometrics**
Facility Type	Condition
Freeway Arterial Collector Local	TxDOT Bridge Project Development Manual

**Table B-10: 4R Sag Vertical Curve Length¹**
Facility Type	Reference
Freeway Arterial Collector Local	TxDOT Criteria See Figure 4-7 & Table 4-12
Notes:
1. Sag Vertical Curve Length applies to sag vertical curves for the purposes of a 4R Design Waiver. Sag Vertical Curve Length for vertical alignment is a direct correlations with the k-value. If the minimum k-value is satisfied for a sag vertical curve (Figure 4-7), then the Sag Vertical Curve Length is satisfied under usual conditions. For minimum Sag Vertical Curve Lengths at Under-Crossings, see Figure 4-29. See 4.11.5 for additional guidance on comfort criteria.

**Table B-11: 4R Superelevation (Non-rate elements)**
Facility Type	Element	Reference
Freeway Arterial Collector Local	Superelevation Transition Length	TxDOT Criteria See Chapter 4.7.6
Freeway Arterial Collector Local	Superelevation Transition Location	TxDOT Criteria See Chapter 4.7.7

**Table B-12: 4R Guardrail Length¹**
Facility Type	Reference
Freeway Arterial Collector Local	TxDOT Criteria See Chapter 17.3- Longitudinal Barriers
Notes:
1. Unless for access accommodation.

**Table B-13: TxDOT's 4R Non-Controlling Criteria for Bicycle Facilities (Minimum)**
Facility Type	Facility Type	Criteria	Reference
Arterials Collectors Local	Shared Use Path Width	10-ft²	See RDM chapter 18 section 18.4.1 for further guidance
	Separated Bike Lane/Buffered Bike Lane Width DS ≤ 45mph DS >45mph	----- -----	See RDM chapter 18 section 18.4.2 for further guidance
	Bike Accessible Shoulder Width DS ≤ 45mph¹ DS >45mph¹ Shoulders adjacent to bridge rail, MBGF, and other vertical elements	4-ft 5-ft 5-ft	See RDM chapter 18 section 18.4.6 for further guidance
Notes:
1. DS stands for design speed
2. In rare cases meeting the following conditions 8-ft minimum may be used. - Bicycle traffic is expected to be low < 50 bicyclist/hour - Pedestrian use of the facility is not expected to be more then occasional or less than 30% of total path traffic - Horizontal and vertical alignments provide frequent passing and resting opportunities where the width is at least 10-ft - The path will not be regularly subjected to maintenance vehicle loading conditions that would cause pavement edge damage

**Table B-14: 3R Design Speed (Minimum)¹**
Facility Type	Additional Factors	Design Speed	Reference
Freeway	----	----	See Table A-1 for 4R Criteria in Appendix A
Arterials Collector Local	Rural: 2-Lane 4-Lane Undivided 4-Lane Divided 6-Lane Divided	30 MPH 50 MPH 50 MPH 50 MPH	TxDOT Criteria
Arterials Collector Local	Rural Town Suburban Urban Core Urban	30 MPH	TxDOT Criteria
Frontage Roads	Rural	30 MPH	TxDOT Criteria
Frontage Roads	Suburban Urban	30 MPH	TxDOT Criteria
Notes:
1. Applicable to low volume (ADT < 1500) roadways.

**Table B-15: 3R Horizontal Curve Radius (Minimum)¹**
Facility Type	Superelevation, emax	Curve Radius (feet) for Design Speed (mph)															Reference
Facility Type	Superelevation, emax	15	20	25	30	35	40	45	50	55	60	65	70	75	80	85	Reference
Low-speed Rural Town, Suburban, urban and Urban Core Facilities	0.04	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	See Table A-4 for 4R Criteria in Appendix A
	NC	--	--	--	--	--	--	--		--	--	--	--	--	--	--	See Table A-4 for 4R Criteria in Appendix A
High-speed Suburban and Urban Facilities	0.04	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	See Table A-4 for 4R Criteria in Appendix A
Rural and High-speed Suburban, urban and Urban Core Facilities	0.06	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	See Table A-4 for 4R Criteria in Appendix A
	0.08	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	See Table A-4 for 4R Criteria in Appendix A
Notes:
1. Applicable to low volume (ADT < 1500) roadways.

**Table B-16: 3R Stopping Sight Distance (SSD) (Minimum)¹**
Facility Type	Design Speed (mph)															Reference
Facility Type	15	20	25	30	35	40	45	50	55	60	65	70	75	80	85	Reference
Stopping Sight Distance (feet) for Design²	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	See Table A-6 for 4R Criteria in Appendix A
Notes:
1. Applicable to low volume (ADT< 1500) roadways.

**Table B-17: 3R Maximum Grade¹**
Facility Type	Additional Factors	Terrain	Minimum Grade (%) for Design Speed (mph)															Reference
Facility Type	Additional Factors	Terrain	15	20	25	30	35	40	45	50	55	60	65	70	75	80	85	Reference
Freeway	Rural and Urban	Level	---	---	---	---	---	---	---	---	---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
Freeway	Rural and Urban	Rolling	---	---	---	---	---	---	---		---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
Arterial	Rural	Level	---	---	---	---	---	---	---	---	---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
	Rural	Rolling	---	---	---	---	---	---	---	---	---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
	Urban	Level	---	---	---	---	---	---	---	---	---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
	Urban	Rolling	---	---	---	---	---	---	---	---	---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
Collector	Rural	Level	---	---	---	---	---	---	---	---	---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
	Rural	Rolling	---	---	---	---	---	---	---	---	---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
	Urban	Level		---	---	---	---	---	---	---	---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
	Urban	Rolling	---	---	---	---	---	---	---	---	---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
Local	Rural	Level	---	---	---	---	---	---	---	---	---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
	Rural	Rolling	---	---	---	---	---	---	---	---	---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
	Rural Town, Suburban, Urban, Urban Core	All	---	---	---	---	---	---	---	---	---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
	Rural Town, Suburban, Urban, Urban Core	All	---	---	---	---	---	---	---	---	---	---	---	---	---	---	---	See Table A-6 for 4R Criteria in Appendix A
Notes:
1. Applicable to low volume (ADT < 1500) roadways

**Table B-18: 3R Superelevation (Non-rate elements)¹**
Facility Type	Element	Reference
Freeway Arterial Collector Local	Superelevation Transition Length	TxDOT Criteria See Chapter 4.7.6
Freeway Arterial Collector Local	Superelevation Transition Location	TxDOT Criteria See Chapter 4.7.7
Notes:
1. Applicable to low and high volume roadways

**Table B-19: Bridge Width¹**
Facility Type	Reference
Freeway Arterial Collector Local	See TxDOT Bridge Project Development Manual
Notes:
1. Applicable to low and high volume roadways

**Table B-20: Deficient Bridge Rail¹**
Facility Type	Reference
Freeway Arterial Collector Local	See TxDOT Bridge Project Development Manual
Notes:
1. Applicable to low volume (ADT < 1500) roadways

**Table B-21: 3R Clear Zone (Minimum)¹**
Facility Type	Additional Factors	Clear Zone	Reference
Freeways	--------------- --------------- ---------------	---------------	See 4R criteria values
Arterials Collectors Local	Rural: 2-Lane Current ADT < 1500 Current ADT ≥ 1500	7-ft 10-ft	TxDOT Criteria
	4-Lane Undivided 4-Lane Divided 6-Lane Divided	16-ft	TxDOT Criteria
	Rural Town Suburban Urban Core Urban	To back of curb or outside edge of shoulder	TxDOT Criteria
Frontage Roads	Rural: Current ADT < 1500 Current ADT ≥ 1500	7-ft 16-ft	TxDOT Criteria
Frontage Roads	Suburban Urban	To back of curb or outside edge of shoulder	TxDOT Criteria
Notes:
1. Applicable to low volume and high volume roadways.

**Table B-22: 3R Speed Change Lane Width (Minimum)¹**
Facility Type	Additional Factors	Clear Zone	Reference
Freeways	--------------- --------------- ---------------	---------------	See 4R criteria values
Arterials Collectors Local	Rural: 2-Lane Current ADT < 1500 Current ADT ≥ 1500	7-ft 10-ft	TxDOT Criteria
	4-Lane Undivided 4-Lane Divided 6-Lane Divided	16-ft	TxDOT Criteria
	Rural Town Suburban Urban Core Urban	To back of curb or outside edge of shoulder	TxDOT Criteria
Frontage Roads	Rural: Current ADT < 1500 Current ADT ≥ 1500	7-ft 16-ft	TxDOT Criteria
Frontage Roads	Suburban Urban	To back of curb or outside edge of shoulder	TxDOT Criteria
Notes:
1. Applicable to low volume and high volume roadways.

**Table B-23: 3R Length of Speed Change Lanes (Minimum)¹**
Facility Type	Reference
Arterials and Collectors	TxDOT Criteria See 4.10.2 and Table 4-14
Notes:
1. Applicable to low volume and high volume roadways.

**Table B-24: 3R Curbside Parking Lane Width (Minimum)¹**
Facility Type	Additional Factors	Parking Lane Width	Reference
Arterials and Collectors	Rural Town Urban Core Urban	7-ft²	TxDOT Criteria
Notes:
1. Applicable to low volume and high volume roadways.
2. In commercial and industrial areas an 8-ft minimum width should be used.

**Table B-25: 3R Guardrail Length¹**
Facility Type	Reference
Freeway Arterial Collector Local	TxDOT Criteria See Chapter 17.3 - Longitudinal Barriers
Notes:
1. Applicable to low volume and high volume roadways.
2. Unless for access accommodation.

**Table B-26: 3R Sag Vertical Curve Length^1,2**
Facility Type	Reference
Freeway Arterial Collector Local	TxDOT Criteria See Figure 4-7 & Table 4-12
Notes:
1. Applicable to low volume and high volume roadways.