Date: 201807
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Situational Awareness
Second reporter function: Pilot Flying; Captain
Anomaly: ATC Issue All Types; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Requested ATC Assistance / Clarification
Contributing factors: ATC Equipment / Nav Facility / Buildings; Airport
Primary problem: ATC Equipment / Nav Facility / Buildings

Narrative: Cleared for takeoff on Runway ZZR after lineup and wait. On takeoff roll around 50 knots and very low speed; we both noticed red runway incursion lights came on. The lights were OFF when we were cleared for takeoff and initiated takeoff roll procedures. Tower said nothing over radio. Conditions were day VMC with clear visibility to the end of the runway. As FO (First Officer); I cannot call for a reject; but what I immediately did was that I queried tower 'red lights on ZZR.' Tower replied with 'roger' and did not give any additional verbiage. At this point; we were approaching 100 knots and CA (Captain) elected to continue as we had no indications of a runway incursion or unsafe situation and we had clear visibility of a safe and clear runway. I responded with 'continuing' as we had no determined we had a safe runway and there was no unsafe situation or incursion. Mind you; all of this took place from 0 to around 90 knots on takeoff roll with very little time to decide; no time to discuss; and no real SOP or guidance for a situation like this.Per FM; we were still below 100 knots and we had determined we had a safe runway for departure so we continued the takeoff roll based on the information we had.Uneventful takeoff and departure and tower handed us off to departure. On initial climbout; we did hear tower discuss that there was an upcoming arrival on Runway ZZ. Perhaps the inbound aircraft to runway ZZ triggered the false red lights on our takeoff roll.Uneventful flight over to ZZZ. After landing and parking checklist complete; the CA actually called Tower on the phone. They had no issues with what happened and it was a non-event on their end. However; they informed the Captain that they have no indications of the lights being on while an aircraft was in the position that we were in. That is concerning because that situation could have easily resulted in an unnecessary rejected takeoff event when there was no unsafe situation or runway incursion. Thankfully in our situation; we were quickly able to determine we had no incursion or unsafe situation and were able to safely continue the takeoff roll and departure.


Second narrative: Our flight was cleared for takeoff on Runway ZZR. Shortly after the takeoff thrust was set; red runway stop lights appeared. The ATC control tower issued no instructions and no incursion could be seen. The FO (First Officer) (PM [Pilot Monitoring]) queried the tower about 'redlights' and received the response 'Roger.' By this point the aircraft had accelerated considerably. We could see no unsafe conditions and elected to continue. The FO advised the tower 'we are continuing;' we received no response. Once we were airborne an ATC controller mentioned something about an approach on Runway ZZ. The rest of the flight was uneventful.I spoke with the tower ATC on the phone later; they stated that they get no indication of the stop lights in the tower but that arrivals on Runway ZZ can sometimes trigger the runway stop lights.The First Officer and myself felt there was no reason to reject the takeoff and continued without incident. The tower had ample time to cancel the takeoff clearance if there was an actual conflict. In the heat of the moment the decision to continue seemed the safest course.


Synopsis: B737 flight crew reported that red runway stop lights appeared during takeoff roll.