The U.S. has studied the problem of deadly side underride for years and yet side underride guards still are not required by a federal regulation. There are some countries which are definitely further along than we are in the process of providing side underride protection on trucks. Here are some posts and articles on the topic of side guards:

1. Outside Frame Avoids Side Underride Feb 1, 2000 Paul Schenck | Trailer/Body Builders The Safe Liner principle of using outside frame members to act as guard rails was the idea of a safety researcher who has spent a lifetime analyzing vehicle accidents. Dr Karl-Heinz Schimmelpfennig of the engineering firm of Schimmelpfennig and Becke in nearby Munster came up with the concept for the integral safety guard frame and worked with Krone engineers in developing a practical truck trailer with this passive safety restraint.Since last summer, Krone has had five Safe Liners on the road undergoing fleet testing by customers. These outside frame trailers have accumulated 120,000 to 160,000 km (75,000 to 100,000 miles). Another 65 Safe Liners were built in the last half of 1999. Problems have been minimal, Dr Krone says, and fleets are accepting the new concept. Current production is at the rate of two Safe Liners per day (5% of the current production rate of 40 trailers per day). Krone plans to expand this to six per day (15% of daily production) by midyear.The special 38-pallet trailer l5.65-meter (51 feet) that was shown to Chancellor Schroder in June received a good reception in other countries as well. Fleets in Sweden are very interested in the increased productivity. In the Netherlands, a five-truck test under government supervision will investigate whether the longer semitrailer and heavier GVW (60 metric tonnes or 132,000 lb) will actually reduce the number of trucks on the road.Whatever the outcome of the fleet testing of this 38-pallet Safe Liner, the standard-size 34-pallet Safe Liner is already being accepted as a safer vehicle that offers more protection for other road users, including cyclists and pedestrians.
2. Jurors Sideswipe Trailer OEMs
   Bruce Sauer | Trailer/Body Builders

    Dec 1, 2000 IT HAS BEEN an autumn of legal wrangling. While most of the nation focused its attention on dimpled chads and manual recounts, a jury in Laredo, Texas, reached a decision that may impact trailer manufacturers like a Palm Beach County voter taking a stab at a butterfly ballot.

   In a nutshell, the jury found that a trailer was defective because it was not equipped with a side underride guard.

3. Truck Underride Deaths (by type) from DOT Fatality Analysis Reporting System (FARS) 1994-2014 I asked DOT for a breakdown of truck underride deaths by type: front, side, and rear. I just received that chart today.Truck Underride Deaths by TYPE 1994-2014From 1994 to 2014, this is the breakdown of Deaths by Underride:Collision at Front of the Truck: 625Collision at Side of the Truck: 1534Collision at Rear of the Truck: 1715

   Collision Site Unknown: 132

   Total Underride Deaths Reported: 4,006

   Of course, we need to remember that these figures do not include all underride deaths as it is well-known that they are commonly under-reported.

   So why are trucks sold without side guards? (Why on earth would this be an optional feature?!) And why does NHTSA not mandate side guards?

   Sign our petition to NHTSA to initiate rulemaking on side guards: End Deadly Truck Side Underride Crashes: Mandate Side Guards

4. Side Guards: The original intent of NHTSA rulemakers in the 1969 NPRM, Docket No. 1-11; Notice 2
5. https://annaleahmary.com/tag/side-guards/
6. Truck Trailer Manufacturers Ass’n “Reminds” NHTSA: Side Guards Are “Not Cost-Effective” Says Who?
7. What about truck SIDE GUARDS and protection for pedestrians & cyclists?
8. TRUCK SIDEGUARDS COUNCIL OF THE EUROPEAN COMMUNITIES DIRECTIVE; The Jessica Campaign
9. ‘UNDERGUARD Protection System’ for Trucks, Generally EEC Directive Compliant
10. Report from Volpe National Transportation Systems Center: “Side Guards Save Lives; A Success Story”
11. Piercing the Passenger Compartment–Voluntary Efforts to Stop the Horrors of Underride Truck Crashes
12. Powerful & Informative Case Made for Underride Guard Improvement by Trucker/Attorney
13. Make your lorry safe for cyclists or pay up, warns Boris
14. Truck Side Guards Resource Page Side guards have been required standard equipment since the 1980s in the European Union and Japan, and more recently in Brazil. Canada conducted research for a national side guard standard from 2009 to 2013 and also began evaluating the viability of using aerodynamic side skirts for vulnerable road user safety.
15. Side Guards Safety Work Nets National Tech Transfer AwardA Volpe team that investigated and promoted life-saving truck side guards for municipalities won a national 2016 Federal Laboratory Consortium (FLC) Excellence in Technology Transfer award.Side guards are vehicle-based safety devices that physically cover exposed areas on the side of a truck, shielding vulnerable road users—such as bicyclists and pedestrians—from being swept underneath a truck’s rear wheels. The Cities of New York, Boston, Cambridge, and San Francisco have taken steps to make truck side guards standard equipment on city vehicles.“We were partners in setting up the technology,” said Dr. Alex Epstein, who led the Volpe team. “Together, we enabled its introduction in the U.S. We had the technical knowledge and expertise to inform their efforts, and to connect with vendors and contractors that could build side guards. From the research phase to the implementation phase, it was a close partnership with these municipalities.”Side guards have been required equipment since the 1980s in the European Union and Japan, and recently in Brazil. After side guards were mandated in the United Kingdom, there was a 61 percent drop in bicyclist fatalities and a 20 percent drop in pedestrian fatalities in side-collisions with trucks.
16. Infographic – Truck Side Guards Save Lives
17. Truck Side Guard Technical Overview Safety and Operational Considerations Side guards have been required standard equipment since the 1980s in the European Union and Japan, and more recently in Brazil. Canada conducted research for a national side guard standard from 2009 to 2013 and also began evaluating the viability of using aerodynamic side skirts for VRU safety. Reports from that effort and from Dutch research suggest that certain side skirts may provide comparable protection while also potentially reducing fuel consumption by reducing air drag.                                                            Side collisions with large trucks were associated with 111 pedestrian and bicyclist fatalities annually in the U.S., based on 2005-2009 data on single-unit trucks and tractor-trailers. Of the 75 fatal bicyclist crashes per year with large trucks, approximately 50 percent were side impacts.                                                                                        Based on studies conducted in the United Kingdom, side guards are an effective technology for reducing the number of VRU fatalities and the severity of injuries, especially for bicyclists. For example, in the UK, a 61 percent reduction in cyclist fatalities and 20 percent reduction in pedestrian fatalities were reported in sideimpact collisions with trucks following the national side guard mandate. 
18. NTSB Safety Recommendations to NHTSA regarding side guards for single-unit trucks (July 3, 2013)
19. NTSB Safety Recommendations to NHTSA regarding side guards for tractor-trailer trucks (April 3, 2014)
20. Dutch Road Safety Research Institute: Closed Sideguards on Trucks: Less Fuel Consumption for Trucks, Safer Feeling for Vulnerable Road Users
21. Great Britain Department for Transport: Integrated Safety Guards and Spray Suppression: Final Summary Report
22. New on the Market: Angel Wing Side Guard Solution To Prevent Truck Underride Deaths & Injuries
23. Could Tesla crash fatality have been prevented if trucks were required to have #sideguards?
24. Tesla driver killed in autopilot crash might still be alive if trailers had side underride guards
25. Potential benefits of underride guards in large truck side crashes.
26. Krone Trailer
27. Truck SIDE GUARDS: Let’s get the debate out in the open. Somebody’s life is depending on it. #VRU
28. https://annaleahmary.com/tag/aaron-kiefer/
29. Just got home from the latest side guard crash test. Watch it here!

Alex Epstein, Volpe Transportation Center:

Side Guards: Saving Lives, Saving Fuel
Volpe engineer Alex Epstein presents the idea of using side guards as a means to make trucks safer.

Will we finally acknowledge that the lack of side guards on large trucks leads to a sentence of Death by Motor Vehicle for unsuspecting victims year after year? Will we finally decide to take action and do what is technologically possible in installing underride protection on large trucks?

Update: Today Show investigative Report on Side Underride, February 7, 2017