diff --git a/selfdrive/locationd/estimators/lateral_lag.py b/selfdrive/locationd/estimators/lateral_lag.py
index bde9bf79f1..e725eea7e2 100644
--- a/selfdrive/locationd/estimators/lateral_lag.py
+++ b/selfdrive/locationd/estimators/lateral_lag.py
@@ -1,9 +1,10 @@
 import numpy as np
+import capnp
 from collections import deque
 from functools import partial, cache
 
 import cereal.messaging as messaging
-from cereal import log
+from cereal import log, car
 from openpilot.selfdrive.locationd.helpers import PoseCalibrator, Pose
 
 BLOCK_SIZE = 100
@@ -18,7 +19,7 @@ MIN_NCC = 0.95
 
 
 @cache
-def fft_next_good_size(n):
+def fft_next_good_size(n: int) -> int:
     """
     smallest composite of 2, 3, 5, 7, 11 that is >= n
     inspired by pocketfft
@@ -54,7 +55,7 @@ def parabolic_peak_interp(R, max_index):
   return max_index + offset
 
 
-def masked_normalized_cross_correlation(expected_sig, actual_sig, mask, n):
+def masked_normalized_cross_correlation(expected_sig: np.ndarray, actual_sig: np.ndarray, mask: np.ndarray, n: int):
   """
   References:
     D. Padfield. "Masked FFT registration". In Proc. Computer Vision and
@@ -112,7 +113,7 @@ def masked_normalized_cross_correlation(expected_sig, actual_sig, mask, n):
 
 
 class Points:
-  def __init__(self, num_points):
+  def __init__(self, num_points: int):
     self.times = deque(maxlen=num_points)
     self.okay = deque(maxlen=num_points)
     self.desired = deque(maxlen=num_points)
@@ -126,18 +127,18 @@ class Points:
   def num_okay(self):
     return np.count_nonzero(self.okay)
 
-  def update(self, t, desired, actual, okay):
+  def update(self, t: float, desired: float, actual: float, okay: bool):
     self.times.append(t)
     self.okay.append(okay)
     self.desired.append(desired)
     self.actual.append(actual)
 
-  def get(self):
+  def get(self) -> tuple[np.ndarray, np.ndarray, np.ndarray, np.ndarray]:
     return np.array(self.times), np.array(self.desired), np.array(self.actual), np.array(self.okay)
 
 
 class BlockAverage:
-  def __init__(self, num_blocks, block_size, valid_blocks, initial_value):
+  def __init__(self, num_blocks: int, block_size: int, valid_blocks: int, initial_value: float):
     self.num_blocks = num_blocks
     self.block_size = block_size
     self.block_idx = valid_blocks % block_size
@@ -146,14 +147,14 @@ class BlockAverage:
     self.values = np.tile(initial_value, (num_blocks, 1))
     self.valid_blocks = valid_blocks
 
-  def update(self, value):
+  def update(self, value: float):
     self.values[self.block_idx] = (self.idx * self.values[self.block_idx] + (self.block_size - self.idx) * value) / self.block_size
     self.idx = (self.idx + 1) % self.block_size
     if self.idx == 0:
       self.block_idx = (self.block_idx + 1) % self.num_blocks
       self.valid_blocks = min(self.valid_blocks + 1, self.num_blocks)
 
-  def get(self):
+  def get(self) -> float | None:
     valid_block_idx = [i for i in range(self.valid_blocks) if i != self.block_idx]
     if not valid_block_idx:
       return None
@@ -163,10 +164,10 @@ class BlockAverage:
 class LateralLagEstimator:
   inputs = {"carControl", "carState", "controlsState", "liveCalibration", "livePose"}
 
-  def __init__(self, CP, dt,
-               block_count=BLOCK_NUM, min_valid_block_count=BLOCK_NUM_NEEDED, block_size=BLOCK_SIZE,
-               window_sec=MOVING_WINDOW_SEC, okay_window_sec=MIN_OKAY_WINDOW_SEC, min_recovery_buffer_sec=MIN_RECOVERY_BUFFER_SEC,
-               min_vego=MIN_VEGO, min_yr=MIN_ABS_YAW_RATE, min_ncc=MIN_NCC):
+  def __init__(self, CP: car.CarParams, dt: float,
+               block_count: int = BLOCK_NUM, min_valid_block_count: int = BLOCK_NUM_NEEDED, block_size: int = BLOCK_SIZE,
+               window_sec: float = MOVING_WINDOW_SEC, okay_window_sec: float = MIN_OKAY_WINDOW_SEC, min_recovery_buffer_sec: float = MIN_RECOVERY_BUFFER_SEC,
+               min_vego: float = MIN_VEGO, min_yr: float = MIN_ABS_YAW_RATE, min_ncc: float = MIN_NCC):
     self.dt = dt
     self.window_sec = window_sec
     self.okay_window_sec = okay_window_sec
@@ -196,12 +197,12 @@ class LateralLagEstimator:
 
     self.reset(self.initial_lag, 0)
 
-  def reset(self, initial_lag, valid_blocks):
+  def reset(self, initial_lag: float, valid_blocks: int):
     window_len = int(self.window_sec / self.dt)
     self.points = Points(window_len)
     self.block_avg = BlockAverage(self.block_count, self.block_size, valid_blocks, initial_lag)
 
-  def get_msg(self, valid, debug=False):
+  def get_msg(self, valid: bool, debug: bool = False) -> capnp._DynamicStructBuilder:
     msg = messaging.new_message('liveDelay')
 
     msg.valid = valid
@@ -222,7 +223,7 @@ class LateralLagEstimator:
 
     return msg
 
-  def handle_log(self, t, which, msg):
+  def handle_log(self, t: float, which: str, msg: capnp._DynamicStructReader):
     if which == "carControl":
       self.lat_active = msg.latActive
     elif which == "carState":
@@ -282,10 +283,7 @@ class LateralLagEstimator:
     self.block_avg.update(delay)
     self.last_estimate_t = self.t
 
-  def correlation_lags(self, sig_len, dt):
-    return np.arange(0, sig_len) * dt
-
-  def actuator_delay(self, expected_sig, actual_sig, mask, dt, max_lag=1.):
+  def actuator_delay(self, expected_sig: np.ndarray, actual_sig: np.ndarray, mask: np.ndarray, dt: float, max_lag: float = 1.) -> tuple[float, float]:
     assert len(expected_sig) == len(actual_sig)
     max_lag_samples = int(max_lag / dt)
     padded_size = fft_next_good_size(len(expected_sig) + max_lag_samples)