Riverside Patrol

I use the 2011 CVPI and ELS. I assume you used OpenIV to install the car, but just to be sure, make sure you followed these steps:
 
1. Open OpenIV for GTA V
2. Navigate to GTA V > Update > x64 > dlcpacks > patchday14ng > dlc.rpf
3. Click "Edit Mode"
4. Click "Add to Mods Folder"
5. Navigate to GTA V > mods > Update > x64 > dlcpacks > patchday14ng > dlc.rpf > x64 > levels > gta5 > vehichles.rpf
6. Drop all of the .yft and .ytd files into that directory [Close OpenIV, no longer needed]
7. Copy the included "police.xml" file to GTA V > ELS > pack_default
 
The steps above will create a folder for you to safely add vehicles without tampering with game files, and add the ELS config file for the 2011 CVPI to the ELS folder.
 
For some computers with lower vRAM or RAM capacity, spawning these vehicles can be slow, and lead to texture loss. GTA V will try to avoid spawning these resource intensive cars naturally, based on your GTA V video settings, and GCARD capabilities.
 
I highly recommend that you download Simple Native Trainer (requires ScriptHook) so you can manually spawn your cars, among other things.
 
If you are having problems getting ELS to work, try the following:
 
Update OpenIV, and install the latest .asi loaders [Its under Tools in OpenIV]
Update Rage Plugin Hook to the latest version.
Make sure you have the latest AdvancedHook [Included with your ELS Download]
 
Note: By default press J to toggle the different light stages, G to toggle the siren, 1 through 6 to manually toggle sirens, and T and Y for horn/man
 
~Hope this Helps

It's damned if you do, damned if you don't. Release a mod early in its progress, and people complain that it doesn't have all the features they expected or that it has bugs. Release updates too often and people complain that you are just trying to get more downloads. Release a mod before it has a lot of variation in the callouts and people complain that it's boring. Wait until a mod is actually polished and release-ready and people complain that you're being greedy. Quite frankly, I'm tired of people who have never contributed a useful or complex mod in their life complaining and acting entitled like this. I will release my mod when I am happy with the level of polish. That's my decision to make. But since people seem to feel the need to attack the legitimacy of having an extended beta, let me share some additional information with you: 
I have not yet finished making an automated installer for the DLC that comes with the mod. The installation process is very complex; most of my beta testers have had some sort of issues with the process, and I've had to give support to most of them. If I released the mod to the public now and had 1000s of users, there would be no end of complaints about how difficult it is to install. A limited beta controls the number of people who need to be helped. I don't feel comfortable releasing something with such a convoluted installation process to the public at large, both because it's unfair to users who expect a released mod to work properly, and because I don't have time to support the inevitable numbers of people who wouldn't be able to figure it out.  I have released 25 updates to the beta since it started in January. I often release multiple updates in one day, in fast response to issues that beta testers have encountered or as I add new features. That kind of update frequency isn't compatible with a public release. I have methods in place to ensure that beta testers are updating frequently, but with released mods people a) don't like to update once they get a stable setup, and b) often don't notice that a new update is available on the site.  Videos show the best parts of a new mod. People don't record the bugs, the hours of frustration trying to get something to install correctly, the features that aren't complete yet, the game crashes, etc.  But none of that really matters anyways. I don't owe you or anyone else anything. Those of us who develop mods do so for our own enjoyment and enhancement of the game. Usually we choose to share those mods with others so they too can have that enjoyment, but it's our right to choose what to share, when, and with whom. If a developer feels their mod isn't yet complete enough to release, that's their right. I've noticed that the only people who complain about this are people who have never actually developed anything themselves, and simply expect the community to give them everything now, for free, working perfectly, with free support, etc. Honestly, if we wanted to, we could make all our mods only available to people who buy them. Many modding communities are like that! I'm proud of the collaborative spirit among lspdfr plugin developers, and I'm glad that mods have always been freely available to anyone who wants to enjoy them, once the mod is ready. I've said before, and I'll reaffirm now, Coastal Callouts will be freely available when I feel the mod is ready, because I want you to all be able to enjoy it. Just be patient. 
 
I'd like to get back to the topic of actually discussing the mod that's under development, so if anybody else has any issues with the concept of people getting rewarded by mod authors for choosing to donate to support their work, feel free to send me a PM or post a separate discussion topic elsewhere. But please stop whining about it in my WIP thread. This has gone way too far off-topic, and frankly I have no interest in continuing to belabor the point with people who have no idea how much time and effort it takes to make a good modification.