A guardrail used in many highways and interstates in Tennessee is continuing to cause controversy coming off the death of a teenager.

Back in November, 17-year-old Hannah Eimers was killed when her vehicle went off Interstate 75 in McMinn County and struck a X-Lite guardrail. The impact impaled the guardrail into Eimers vehicle, killing her instantly.

The X-Lite guardrail was developed by a Nebraska-based company named Lindsay Corporation. Basic guardrails used across the nation are designed to redirect the end of the guardrail away from vehicles that hit them. But the Lindsay X-Lite guardrail has done the opposite in at least four documented accidents in the state in the last year and a half.

One of them occurred in Cumberland County last year.

In the early morning hours of June 29, 2016, the Tennessee Highway Patrol responded to a vehicle accident at the 315 mile marker of Interstate 40 near Crossville where 18-year-old Jacob D. Davidson of North Carolina and 21-year-old Lauren A. Beuttel of Johnson City were both killed. Officers say a X-Lite guardrail impaled the vehicle the two was in upon impact.

Not even a week later, another similar accident on the interstate in Hamilton County resulted in one death.

After the Hamilton and Cumberland County accident, state road crews replaced the damaged X-Lite guardrail with another one.

In October 2016, the Tennessee Department of Transportation removed the controversial guardrails from their approval list of devices to use. The reason was “concerns about potential long-term performance” when struck at speeds greater than 45 miles per hour. Prior to that decision, TDOT estimates around 1,000 of the guardrails have already been installed on highways and interstates in Tennessee.

TDOT has a plan in place now to remove the X-Lite guardrails that has been installed on any highway or interstate with a minimum speed limit of 45 miles per hour. According to TDOT, this plan will eliminate the vast majority of the ones installed, but not all of them. Work is expected to start in the summer on the removal and replacement of the X-Lite guardrails with safer guardrails.

Lindsay Corporation issued a statement after the accidents defending its safety record and noting that the X-LITE terminal remains in compliance with federal standards. Company officials said the terminal has passed all crash and safety tests.

In the meantime, lawmakers in states that the X-Lite guardrails are currently on the roads have introduced bills to either ban the use of the controversial guardrails in their states or eliminate the existing ones from the roadways. In other states such as Tennessee, the state road departments are discontinuing use of the X-Lite guardrails.

But the X-Lite guardrail is not the only threat when it comes to safe guardrails in Tennessee.

There is another one that is also not on the Tennessee Department of Transportation’s qualified product list. It is the ET Plus system. It was taken off in 2014 after the federal government told the company more crash testing was needed. Currently, there are just over 21,000 ET Plus terminals installed across Tennessee.