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ATP 3-34.81MCWP 3-17.4Engineer ReconnaissanceMARCH 2016DISTRIBUTION RESTRICTION: Approved for public release; distribution is unlimited.This publication supersedes FM 3-34.170/MCWP 3-17.4, 25 March 2008.Headquarters, Department of the Army

FOREWORDThis publication has been prepared under our direction for use by our respective commands and othercommands as appropriate.JAMES H. RAYMERBrigadier General, USACommandantU.S. Army Engineer SchoolROBERT S. WALSHLieutenant General, USMCDeputy Commandant forCombat Development and IntegrationThis publication is available at Army Knowledge Online https://armypubs.us.army.mil/doctrine/index.html .To receive publishing updates, please subscribe at http://www.apd.army.mil/AdminPubs/new subscribe.asp .It is also available at the U.S. Marine Corps Web siteat Marine Corps Doctrine at https://www.doctrine.usmc.mil/

ATP 3-34.81/MCWP 3-17.4 , C1Change 1Army Techniques Publication No. ATP 3-34.81/MCWP 3-17.4HeadquartersDepartment of the ArmyWashington, DC, 30 January 2017Engineer Reconnaissance1. This change corrects the spelling of cord to chord. It also corrects formulas used in chapter 4.2. A bar ( ) marks new or changed material.3. ATP 3-34.81/MCWP 3-17.4 is changed as follows:Remove Old Pagesii4-7 through 4-9Insert New Pagesii4-7 through 4-94. File this transmittal sheet in front of the publication for reference purposes.DISTRIBUTION RESTRICTION: Approved for public release; distribution is unlimited.

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ATP 3-34.81, C1MCWP 3-17.430 January 2017By Order of the Secretary of the Army:MARK A. MILLEYGeneral, United States ArmyChief of StaffOfficial:GERALD B. O’KEEFEAdministrative Assistant to theSecretary of the Army1701811DISTRIBUTION:Active Army, Army National Guard, and United States Army Reserve: Distributed in electronic mediaonly (EMO).PCN: 14300015600PIN: 106039 001

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*ATP 3-34.81MCWP 3-17.4Army Techniques PublicationNo. 3-34.81HeadquartersDepartment of the ArmyWashington, DC, 1 March 2016Marine Corps Warfighter PublicationNo. 3-17.4Engineer ReconnaissanceContentsPagePREFACE. vINTRODUCTION . viChapter 1ENGINEER RECONNAISSANCE FRAMEWORK . 1-1Engineer Reconnaissance Tasks . 1-1Engineer Reconnaissance Team Capabilities and Limitations . 1-4Command and Support Relationships . 1-7Sustainment Considerations . 1-8Chapter 2ENGINEER SUPPORT TO INFORMATION COLLECTION/INTELLIGENCE,SURVEILLANCE, AND RECONNAISSANCE . 2-1Planning . 2-1Staff Support . 2-1Reconnaissance . 2-2Chapter 3RECONNAISSANCE SUPPORT . 3-1Support to Mobility . 3-1Support to Countermobility . 3-8Support to Survivability . 3-9Support to Other Environments and Activities. 3-9Support to Other Reconnaissance Types . 3-18Chapter 4TECHNICAL RECONNAISSANCE—ROUTE CLASSIFICATION . 4-1Route Classification . 4-1Curve Calculations . 4-6Underpasses . 4-15Tunnels on Routes . 4-15Road Reconnaissance . 4-18Base Course and Subgrade . 4-22Chapter 5TECHNICAL RECONNAISSANCE—ASSESSMENTS AND SURVEYS . 5-1Bridge Reconnaissance. 5-1Distribution Restriction: Approved for public release; distribution is unlimited.*This publication supersedes FM 3-34.170/MCWP 3-17.4, 25 March 2008.1 March 2016ATP 3-34.81/MCWP 3-17.4i

ContentsOther Gap-Crossing Sites . 5-2Engineer Resource Assessment. 5-10Infrastructure Reconnaissance . 5-10Environmental Reconnaissance . 5-16Airfield Assessment. 5-16Appendix AMETRIC CONVERSION CHART . A-1Appendix BREPORTING . B-1Appendix CINFRASTRUCTURE RECONNAISSANCE . C-1Appendix DMILITARY LOAD CLASSIFICATION. D-1Appendix ETECHNICAL TOOLS AND RESOURCES . E-1Appendix FSIGNS . F-1GLOSSARY . Glossary-1REFERENCES. References-1INDEX . Index-1FiguresFigure 1-1. Range of engineer reconnaissance capabilities . 1-2Figure 2-1. Route reconnaissance graphic control measures . 2-5Figure 2-2. Zone reconnaissance graphic control measures. 2-7Figure 2-3. Area reconnaissance graphic control measures . 2-8Figure 4-1. Route classification overlay . 4-3Figure 4-2. Route widths . 4-5Figure 4-3. Tape-measure method . 4-7Figure 4-4. Triangulation method . 4-8Figure 4-5. Chord method . 4-9Figure 4-6. Curve symbols . 4-9Figure 4-7. Percent of slope format . 4-10Figure 4-8. Map method to determine percent of slope . 4-11Figure 4-9. Pace method to determine percent of slope. 4-12Figure 4-10. Angle-of-slope method to determine percent of slope . 4-13Figure 4-11. Percent-of-slope symbols . 4-14Figure 4-12. Route construction symbol . 4-14Figure 4-13. Underpass symbols . 4-15Figure 4-14. Types of tunnel bores . 4-16Figure 4-15. Tunnel symbols . 4-16Figure 4-16. Overhead clearance measurements . 4-17Figure 4-17. Dimensions required for tunnels . 4-18Figure 4-18. Portal view of tunnel . 4-19Figure 4-19. Parts of a road . 4-19iiATP 3-34.81/MCWP 3-17.4, C130 January 2017

ContentsFigure 4-20. Load bearing capacity of roads with a flexible surface . 4-22Figure 5-1. Telltale . 5-2Figure 5-2. Ford symbols . 5-4Figure 5-3. Ferry symbols . 5-6Figure 5-4. Sample ferry symbols. 5-6Figure 5-5. Dimensions required for streams and rivers . 5-7Figure 5-6. Compass method to measure width of stream . 5-8Figure 5-7. Measuring gap width with a surveying instrument . 5-8Figure 5-8. Finding stream velocity . 5-9Figure 5-9. Assessment overlapping survey . 5-11Figure 5-10. Airfield damage categories . 5-17Figure B-1. Sample DD Form 3009 .B-5Figure B-2. Sample DD Form 3010 .B-12Figure B-3. Sample DD Form 3011 .B-15Figure B-4. Typical bridge spans .B-18Figure B-5. Sample DD Form 3012 .B-20Figure B-6. Sample DD Form 3013 .B-23Figure B-7. Sample DD Form 3014 .B-26Figure B-8. Sample DD Form 3015 .B-29Figure B-9. Engineer resource symbols .B-31Figure B-10. Sample DD Form 3016 .B-33Figure C-1. The infrastructure assessment and survey model . C-1Figure E-1. ENFIRE components .E-4Figure F-1. Hazard signs not included in the Geneva Convention. F-2Figure F-2. Hazard signs included in the Geneva Convention . F-3Figure F-3. Warning and enforcement signs . F-3Figure F-4. Bridge signs . F-4Figure F-5. Width and height signs . F-5Figure F-6. Bridge sign containing technical information . F-5Figure F-7. Typical multilane bridge classification. F-6Figure F-8. Indicators of a damaged bridge . F-6Figure F-9. Military route guide signs for axial routes . F-7Figure F-10. Directional disks . F-8Figure F-11. Guide signs for casualty evacuation routes . F-8Figure F-12. Unit direction arrow . F-9Figure F-13. Military detour signs . F-9Figure F-14. Front sign .

1. This change corrects the spelling of cord to chord. It also corrects formulas used in chapter 4. 2. A bar ( ) marks new or changed material. 3.ATP 3-34.81/MCWP 3-17.4 is changed as follows: Remove Old Pages _ Insert New Pages_ ii 4-7 through 4-9 ii 4-7 through 4-9 4. File this transmittal sheet in front of the publication for .