The engine revs and the sirens blare.
Major Kyle Simpson pushes the accelerator and speeds through the tight streets of Old Louisville.
A few miles north, on the fifth floor of a downtown hotel, a man is overdosing.
"Snorted heroin," said Simpson, a paramedic and supervisor with Louisville Metro EMS.
Runs like this are more common than ever for emergency crews in Louisville and many cities across the country.
In fact, crews in Louisville were dispatched to more than 4,200 suspected overdose incidents in the first five months of 2017 - nearly 1,000 more than during the same time period last year and more than double the number in 2015, according to city data.
Simpson says they can happen anywhere and anytime - parking lots and public bathrooms, the suburbs or the local jail.
The prevalence of overdoses and the struggle to stop them has prompted a partnership between Louisville Metro government and the federal Office of National Drug Control Policy's High Intensity Drug Trafficking Areas program.
City officials will use software developed by the federal agency to create a real time map of where overdoses are occurring - updated by EMS crews on the street.
The tool will help alert hospital staff, police and other first responders when overdose spikes occur, said Mitchell Burmeister, spokesman for Louisville Metro Emergency Services.
What's more, law enforcement could use the mapping tool to track the flow of drugs across the city - and country.
But the map won't be available to the public, Burmeister said.
"It's really meant for internal tracking and to increase our coordination," he said.
Data Is 'Open By Default.' Just Not This Data.
The move is counter to the city's broader initiative and aspiration to be a leader in making city data open and available to the public.
Louisville Mayor Greg Fischer in 2013 issued an executive order calling for all public data to be "open by default."
The directive has led to more than 200 datasets being published online - from crime to code enforcement violations, to city employee turnover and animal registration.
So, why won't the overdose map be public?
Burmeister said it's due to the sensitive information collected by emergency crews during overdose incidents.
"There is protected health information on this map," he said. "We can't release that information."
Still, he said the agency has the ability to "deidentify" the data and remove specificity that would allow purveyors to identify victims—but there are not immediate plans to do so.
'You can't be too careful'
Margeaux Spring understands the concerns associated with citizens' health information.
She's a co-captain of the Civic Data Alliance, a local group that advocates for open, accessible public information.
Spring said she'd rather wait for the data to be aggregated than risk exposing data not meant for public consumption.
"You can't be too careful," she said.
Patrick Smith, a core member of the Civic Data Alliance, agreed that aggregated data is imperative. But, he said city officials should make publicly available a map of overdose hot spots.
"Such a map would be hugely valuable to community organizations looking to target prevention efforts, outreach or interventions serving areas with a high intensity of overdoses," he said.
Major Kyle Simpson with Louisville's EMS said providing the public with such a tool could be beneficial to help residents recognize where drug instances are happening. He said visualizing that information could serve as "a wake up call."
"It's really an epidemic here," he said.
Police and fire crews are already on the scene when he arrives at the downtown Louisville hotel shortly before sunset.
Before he climbs out of the driver's seat the radio crackles—as it often does during the shift.
The next call is another overdose.
