WASHINGTON The second phase of a National Highway Traffic Safety Administration crash testing program for motorcoaches will get under way this month at a testing facility in Ohio.

Engineers plan to conduct nine separate sled tests so they can examine seat and seatbelt anchorage loads and the impact accidents have on belted and unbelted passengers seated in various locations on a full-size coach.

The tests are part of an extensive three-part study the NHTSA plans to use to address a long list of safety issues, ranging from the use of seatbelts on coaches to new design standards for coaches.

The sled tests follow crash and rollover testing the NHTSA did in December using five older model coaches one more than originally planned to study seatbelt anchorage loads and roof strengths. Those tests opened the three-phase program that early next year will add the final piece of the study, an extended testing of coach fires and their causes.

In this phase of the testing, engineers at the Vehicle Research and Test Center in East Liberty, Ohio, will fit a crash sled with three rows of motorcoach seats with life-size dummies. They then will run nine separate crashes with the dummies seated in various configurations with some wearing lap belts, others wearing three-point restraints and a few unrestrained.

It was not known how long the testing will take or when the results would be available. In the first testing phase, preliminary results were released about a month after the tests were completed.

The NHTSA said the testing was running behind earlier schedules because of the need to collect a large amount of bus data and analyze it so more information could be fed into the testing process.

The flammability tests that will come next year will be geared toward studying how a motorcoach fire spreads into the passenger compartment, identifying interior material flammability, determining the feasibility of establishing requirements for fire-hardening or fire-resistant exterior components, and assessing the tenability of the passenger compartment during a wheel-well fire.

The NHTSA said the tests will focus only on fires that start in the areas near the rear wheel wells and fuel lines because the Swedish National Testing and Research Institute is planning full-scale fire testing of motorcoaches and there is no need to repeat the same tests. Instead, it said results of the wheel-well study will complement the Swedish testing.

The testing process is not scheduled to start until early next year and will take about two years to complete. "There is a fair amount of research and development necessary in preparation for the actual fire testing," noted NHTSA spokesman Eric L. Bolton.

Among the preliminaries are:

An inspection of buses that have been involved in fires

A literature search on material flammability

An evaluation of laboratory test results

An examination of existing requirements for materials used inside coaches

The results of the completed crash tests and the study methodology developed for the upcoming sled and fire tests can be viewed online at www.regulations.gov. Under the heading More Search Options on the right side of the screen, click on Advanced Docket Searches. Put National Highway Traffic Safety Administration in the Agency box and NHTSA-2007-28793 in the Docket ID box and then click on Submit. When the next page appears, click on the highlighted docket number.