- Light bars/electronics/sirens
- Armoring
- Ability to detain suspects
The first is going to be required for every police or sheriff cruiser.
The second will reduce casualties (arguably for both sides) in an armed engagement. Ideally required for any action which could create an armed engagement. Because a minimum of one side is always armed, every encounter can become an armed engagement. Huzzah USA etc. etc.
The third is required if the police officer will ever respond to anything that isn't giving out a parking ticket. Traffic stops can include anything from an armed engagement down to a drunk driver or peaceful execution of an outstanding warrant. Then there's simple responding to calls, which can also include all of the above.
The lack of ability to detain someone means you need (as stated in the article) more officers responding to an engagement.