Here is some safety information from wikipedia regarding the RL. It's safe to say the past RL was a very safe car. I'm expecting the RLX to raise the bar even further.
From 2005 to 2008, Acura RL has been ranked #1 and has achieved the best car safety score (46.4) in Informed for LIFE's "2003–2009 Vehicle risk index SCOREs". For both the 2009  and 2010  model years, the Acura RL received a five-star crash safety ratings from the National Highway Traffic Safety Administration (NHTSA). For the 2009 model year, the Acura RL received a Top Safety Pick designation from the Insurance Institute for Highway Safety (IIHS) earning a "Good" — the highest score possible — on frontal offset, side impact and rear crash protection tests. The "Good" scores continued for all tests conducted on the 2010 model. When a roof strength (rollover) evaluation was added to the battery of tests, the RL was rated only "Marginal" in this category, causing it to lose the Top Safety Pick award.
- The Acura RL consistently garnered National Highway Traffic Safety Administration (NHTSA) Five Star (the highest rating) ratings for Frontal, Side and Rollover crash testing. The injury measures on the driver in the front test were some of the lowest ever recorded in a NHTSA test at the time, and were still considered top notch as of 2010.
- The Acura RL consistently earned a green G for "Good" (the highest rating) in Frontal Offset and Side Impact tests conducted by the Insurance Institute for Highway Safety (IIHS).
- The facelifted 2009 Acura RL has revised head restraints, thus improving the rear crash protection rating for the 2005–2008 models from Marginal to Good for the 2009, and earning it recognition as an IIHS Top Safety Pick.
- The Acura RL incorporated most modern, and some unique, safety features including:
- Advanced Compatibility Engineering (ACE) body structure - ACE features extensive use of high-tensile steel and lightweight aluminum components in a front-mounted polygonal main frame, designed to engage vehicles of differing size and weight in a frontal collision and spread the forces through multiple structural pathways, while preventing or minimizing cabin deformation. The Acura RL was the launch vehicle for the ACE body structure. In 2009, all production Acura vehicles featured the ACE body structure. The ACE body structure is one factor in Acura achieving an all time first in US automotive history, winning simultaneous top marks in both Government National Highway Traffic Safety Administration (NHTSA) and Insurance Institute for Highway Safety (IIHS) crash test ratings
- Super Handling-All Wheel Drive (SH-AWD) - In addition to its performance benefits, the front to rear and side to side torque distribution of SH-AWD works actively to keep the car on the desired line
- Anti-lock Braking System - 3-channel ABS
- Vehicle Stability Assist (Honda Acura version of Vehicle Stability Control) - 4 channel VSA integrated with SH-AWD, ABS, yaw, lateral G, speed and steering angle sensors
- Electronic Traction Control (uses individual wheel ABS sensor and engine modulation)
- Electronic Brake-force Distribution (EBD) (redistributes front and rear brake pressures as the situation dictates)
- Brake Assist - "learns" the driver's braking habits, rate of pressure and total pressure applied, then quickly activates full ABS in a perceived panic stop
- Front Air Bags (2 ea) - including two-stage activation which minimizes injury due to deployment geometry (deploying upward rather than forward into the occupant) and speed
- Front Side Air Bags (2 ea) - including Occupant Position Detection System (OPDS)
- Side Curtain Air Bags (2 ea) - for front and rear passengers
- Occupant Position Detection Sensor (OPDS) system - detects weight and positioning of passenger in the front seat and disables the passenger front side air bag deployment if the system calculates that deployment could cause injury to the occupant, such as a child or small-statured adult
- LATCH child seat anchors
- Tire Pressure Monitoring System (TPMS]) - provides individual pressure readings for each tire and tire position in a graphical display, and alerts the driver in the event of low or no pressure
- 5 mph (8.0 km/h) bumpers front and back
- Optional Collision Mitigation Braking System (CMBS) (2006-forward)
- Optional Adaptive Cruise Control (ACC) (2006-forward)
From the 2006 model year forward, the Acura RL features an optional precrash system called the Collision Mitigation Braking System (CMBS), which can alert drivers of objects up to 330 feet ahead. If the driver gets dangerously close and does not take evasive action, the RL first provides visible and audible alerts. If the driver does not respond, the electronic pretensioning seatbelt system tugs on the shoulder belts. If the driver still does not react and the collision is deemed unavoidable, the RL retracts and locks seatbelts and brakes hard. Depending on the situation, all three stages may blend together as if one.
- Optional Michelin PAX System run-flat tires (2006–2008)
The same CMBS millimeter wave radar was also used to operate the optional Adaptive Cruise Control (ACC) feature. The driver selected a cruise speed and could set a timed following distance of 2.0, 1.5 or 1.0 seconds. When the ACC detected a target at any distance up to 330 feet ahead, the engine throttle would be modulated to keep the timed following distance. If throttle modulation did not provide enough slowing, the car would also apply the brakes to help maintain the chosen distance.
From 2006 through 2008, Michelin PAX System run-flat tires were also offered as an option. This system allowed the car to run up to 125 miles (201 km) at 50 miles per hour (80 km/h) with a flat.
Michelin PAX System run-flat tires require special equipment to replace them. Such equipment is available only at a limited number of specially certified tire and car dealerships. In April 2008, Michelin announced that it would discontinue its PAX run-flat tires. Unless special equipment is available, the Acura RL's optional run-flat tires are usually fixed by replacing the entire wheel/tire assembly. Unlike Honda dealers, Acura dealers were not required to become PAX certified service centers, which included expensive training and specialized machinery. Acura dealers would generally take a flat tire/wheel assembly off and put a new PAX System on the vehicle, or refer the customer to the nearest PAX certified facility.
For warranty and safety reasons, it is not recommended that owners of PAX equipped vehicles switch to another type of tire assembly. Both Acura and Michelin have not been forthcoming about how current owners of PAX equipped Acura RLs can address this impasse once the current supply of PAX tires run out. Some hope that the PAX tire supply will not run out and that they will be continued to be produced on a specialty basis, just as the ill-fated Michelin TRX system tires are still produced today.
Reasons for discontinuing the PAX run-flat system were several, one big reason probably being the class-action suit against Honda and Michelin. Other reasons may have been the difficulty in repair and replacement of PAX tires, which are generally special order and require special mount/demount machinery and training, and the paucity of PAX certified dealers throughout the United States. While RLs have reportedly low incidence of complaints with the premium Michelin Pilot MXM4 all season tires, the opposite was true of the top-of-the-line Honda Odyssey Touring model minivan equipped with Michelin Energy LX4 PAX tires that allegedly did not live up to their promise of long tread life and easy replacement. In addition, during this time, Michelin announced that due to the low general acceptance of the PAX technology throughout the industry, new PAX development would be stopped, although tires would be provided for the foreseeable future. Other PAX equipped vehicles include the world's fastest production car, the Bugatti Veyron EB 16.4, and certain Rolls Royce and Audi vehicles.
On the safety front, it is also worth noting that the Honda Legend, the name under which the RL is marketed in most of the rest of the world where there is no Acura brand, offers some additional optional safety features. These include Lane Keeping Assistance System (LKAS), Intelligent Night Vision, front bumper mounted cameras to assist in parking and turning, and a standard pop-up hood for pedestrian safety.
The LKAS can, with the assistance of a front windshield mounted CMOS camera, make small steering adjustments using the car's Electric Power Steering (EPS) system to keep a car in its lane so long as the radius of the turn was more than 220 meters, which was the then-legal minimum in Japan. The LKAS would relinquish control at the slightest steering input by the driver, so the driver retained control at all times.
The night vision system used a separate heads-up type display reflected from the front lower center windshield. Far infrared technology cameras do not require an infrared light source as near infrared technology cameras do, and the software was able to detect human-like figures, surround the image with a red box and give audible caution tones.
Bumper-mounted cameras gave the driver a view out at each front corner to assist in parking, and also to see the amount of clearance down the road if the car were in an alley-like situation, where driver vision around the corner would require moving much of the car out into the path of possible oncoming traffic.
The pop-up hood used a series of sensors that could detect a pedestrian-like object being thrown onto the hood. An actuator popped the hood up at the rear, close to the windshield, 10 cm (4 inches) to help minimize pedestrian injuries, especially head trauma. RL/Legend models in all markets featured energy-absorbing hood and fender supports and deformable windshield wiper pivots to minimize pedestrian injury.