DES MOINES, Iowa (KCRG) — The Iowa DOT is rejecting a recommendation from the Federal Highway Administration asking them not to use certain messages on highway signs.

The Federal Highway Administration recently released an updated 1,100-page manual that spells out how signs and other traffic control devices are regulated. In it, the agency strongly recommends against overhead electronic signs with obscure meanings, references to pop culture or those intended to be funny, the AP reports.

Rather, signs should be “simple, direct, brief, legible and clear,” when relaying important information like warning drivers of crashes overhead, adverse weather conditions and traffic delays, the agency said. Seatbelt reminders and warnings about the dangers of speeding or driving impaired are allowed.

The Iowa DOT has been using the signs for just over a decade now, and believe these signs aren’t a threat.Officials say the point of the signs is to help people remember traffic safety messages. Previously, there was confusion that the FHA was trying to ban these types of messages, but the measure is only a recommendation. The DOT will keep the messages up for now, but could reconsider once more research is available.

The idea originated when the department decided to display the number of traffic deaths.